THE  UNIVERSITY 
OF  ILLINOIS 
LIBRARY 

&7.G  .*!> 

Q^GS^^stS 


REMOTE  STORAGE 


Digitized  by  the  Internet  Archive 
in  2016 


https://archive.org/details/manualofprincipa00wleg_4 


TBEMMiM  mifoL 

8f-Tf£- 


MANUAL 


OF  THE  PRINCIPAL 

INSTRUMENTS 

USED  IN 

REMOTE  STORAGE 

AMERICAN  ENGINEERING  AND  SURVEYING, 

MANUFACTURED  BY 


W.  & L.  E.  GURLEY, 

TROY,  N.  Y. 


TWENTY-FIFTH  EDITION, 


TROY,  N.  Y. 

PUBLISHED  BY  W.  & L.  E.  GURLEY, 
1884. 


Entered,  according  to  Act  of  Congress,  in  the  year  1884, 
By  W.  & L.  E.  GURLEY, 

In  the  Office  of  the  Librarian  of  Congress,  at  Washington. 


BENJ.  D.  BENSON, 
Printer  and  Stationer, 
27  Maiden  Lane,  N.  Y. 


~^j  O O " *7  w »-•  <->  ' > ) I.J 


PRICE  LIST. 

TRO  J-A.  1ST  XT -A.  IE*,  Y,  1884. 


ALL  PRICES  IN  THIS  WORK  ARE  IN  U.  S.  CURRENCY.  STATE  WHAT  EDITION  OP 

Manual  when  ordering  goods  ; also  give  Catalogue  Number. 


This  Trice  List  supersedes  all  previous  editions, 

TRANSITS. 

No.  Price 

1.— Engineers’,  two  verniers  to  limb,  4 inch  needle*  plain  telescope,*  level- 
ing tripod $145  00 


2.— 

do 

do 

do 

4* 

do 

do 

do 

150  00 

3.— 

do 

do 

do 

5 

do 

do 

Fig.  1. . . 

150  00 

4.— 

do 

do 

do 

5 

do 

with  theodolite  axis. . . 

185  00 

5.— 

do 

do 

do 

5 

do 

with  Solar  Attachment 

vertical  arc,  level  on  telescope,  clamp  and  tangent  to  axis  of  telescope 
and  variation  plate,  leveling  tripod,  Fig.  8 250  00 

6. — Light  Mountain  do  4 do  plain  telescope,  and 

patent  extension  tripod 150  oo 

7.  — do  do  do  4 do  with  level,  vertical  arc, 

clamp  and  tangent  to  axis  of  telescope,  and  Solar  Attachment,  and 

patent  extension  tripod,  Fig.  9 245  00 

12.— Surveyors’,  two  verniers  to  limb,  4 do  plain  telescope,  level- 
ing tripod 125  00 

130  00 
130  00 

ver- 
tical circle  on  silver,  reading  with  vernier  to  single  minutes,  level  on 
telescope  with  ground  bubble  and  scale,  and  clamp  and  tangent 

movement  to  axis  of  telescope,  leveling  tripod.  Fig.  19 160  00 

do  do  do  5 do  with  Solar  Attachment, 

vertical  arc,  level  on  telescope,  clamp  and  tangent  to  axis  of  telescope, 

leveling  tripod,  Fig.  22  . . .’  226  00 

-Surveyors’,  one  vernier  to  limb,  4 inch  needle,  plain  telescope,  leveling 

no  oo 

do  do  5 d«  do  do  115  00 

d0  do  5*  do  do  do 


13.- 

do 

do 

do 

5 

do 

do 

do 

14.— 

do 

do 

do 

5* 

do 

do 

do 

15.- 

do 

do 

do 

5 or  5* 

do 

but  with  4^ 

-inch 

16.- 


115  00 


* A “ plain  ’ 


1 telescope  is  one  without  any  of  the  attachments  or  extras,  as  we 
enn  them,  such  as  the  clamp  and  tangent,  vertical  circle  and  level, 


6 W.  & L.  E.  GURLEY,  TROY,  JST.  Y. 

TRANSITS.—  Concluded . 

No.  Price 

23.  — Surveyors’,  one  vernier  to  limb,  5 or  51-inch  needle,  but  with  level  on 

telescope,  and  clamp  and  tangent  movement  to  axis  of  telescope,  level- 
ing tripod,  Fig.  21 $133  00 

24. —  do  do  do  5 do  with  Solar  Attach- 

ment, vertical  arc,  level  on  telescope,  clamp  and  tangent  to  axis  of 
telescope,  leveling  tripod,  Fig.  22 ...  211  00 

28. — Vernier  Transit  Compass,  4 inch  needle,  plain  telescope,  compass  tripod  70  00 

29. —  do  do  do  5 do  do  do  70  00 

30. —  do  do  do  6 do  do  do  75  09 

31. —  do  do  do  6 do  but  with  vertical  circle  read- 

ing to  5 minutes,  level  on  telescope,  and  clamp  and  tangent  movement 
to  axis  of  telescope,  compass  tripod,  Fig.  23 101  00 

EXTRAS  TO  TRANSITS 

35. — Patent  Solar  Attachment $60 

36. — Variation  Plate  furnished  with  new  Engineers’  Transit  when  ordered  . . 4 

37. — Variation  Plate  added  to  any  Engineers’  Transit  sent  for  repairs 15 

38. — Plummet  Lamp  for  Mining  Engineering,  hung  in  gimbals,  Fig.  16 10 

39. — Diagonal  Prism  for  Eye-piece,  Fig.  13 8 

40. — Reflector  for  object-glass  of  Transit  Telescope,  Fig.  12 4 

41. — Vertical  Circle,  34  inches  diameter,  divided  on  silver,  vernier  reading  to 

five  minutes 8 

42. — Vertical  Circle,  44  inches  diameter,  divided  on  silver,  reading  to  single 

minutes 12 

43.  — Vertical  Arc,  6 inches  diameter,  divided  on  silver,  with  vernier,  movable 

by  tangent  screw,  reading  to  30  seconds 18 

44.  — Clamp  and  tangent  movement  to  axis  of  telescope 6 

45. — Gradienter,  combined  with  clamp  and  tangent,  Fig.  18 18 

46. — Level  on  telescope,  with  ground  bubble  and  scale 12 

47.  — Rack  and  pinion  movement  to  eye-piece  5 

48. — Sights  on  telescope,  with  folding  joints 8 

49. — Sights  on  standards  at  right  angles  to  telescope 8 

50. — Detachable  telescope  for  vertical  sighting,  either  Fig.  14  or  15 25 

51. — Graduations  of  limb  on  solid  silver. . 10 

52. —  do  do  to  read  to  20"  or  30" 10 

53  — do  do  to  read  to  10" 30 

54.  — do  on  45-inch  vertical  circle,  to  read  to  20"  or  30" 5 

55. — Jones’  Patent  Latitude  Arc,  with  reversible  level  bubble,  Fig.  11 72 

60.  — Leveling  tripod  head,  with  clamp  and  tangent  movement,  fitted  to  Vernier 

Transit  Compasses,  Nos.  28  to  31  extra  13 

61. — Patent  extension  tripod,  furnished  instead  of  regular  tripod,  with  any 

new  instrum  ent extra  5 

Y LEVELS. 

70.— Fifteen-inch  telescope,  with  leveling  tripod,  Fig.  44  $90 

72.— Eighteen  do  do  do  ...  .......  .....  — .......  UQ 


gggggg  g g 88S8880808888  § 8 88 


W.  & L.  E.  GURLEY,  TROY,  JSi.  Y.  7 

Y LEVELS. — Concluded. 

No.  Price 

73. — Twenty-inch  telescope,  with  leveling  tripod,  Fig.  42 $110  00 

74.  — Twenty-two  do  do  do  115  00 

75. — Architects’  Level,  eleven-inch  telescope,  with  leveling  tripod,  Fig.  45  . . . 45  00 

7G.— Farmers’  or  Drainage  Level,  with  jacob-staff  mountings 15  00 

77. —  do  with  plain  tripod 20  00 

78.  — do  with  tripod  and  leveling  screws,  Fig.  47 25  00 

85._Quick-leveling  tripod  head,  Fig.  67  6 00 

go.—  do  do  when  ordered  with  new  instrument,  either 

Level  or  Transit,  Figs.  65  and  66  5 00 


PLANE  TABLES. 

90.— Plane  Table,  board  24  x 30  inches,  mounted  on  large  tripod,  with  leveling 
socket  and  clamp,  and  with  plumbing  bar,  plummet  and  clamps  for 


paper $45  00 

Combined  compass  and  levels,  with  square  base 15  00 

Alidade  with  compass  sights,  Fig.  56 15  00 

Total $75  00 

91.— Plane  Table,  with  board,  etc.,  as  in  No.  90 $45  00 

Combined  compass  and  levels 15  00 

Alidade  like  No.  90,  supplied  with  telescopic  sight,  No.  132,  with  stadia, 

vertical  circle  to  5 minutes,  level,  and  clamp  and  tangent,  Fig.  57  50  00 

Total $110  00 


92. — Plane  Table,  with  board,  etc.,  like  No.  90.  . . . $45  00 

Combined  compass  and  levels 15  00 

Alidade  with  telescope  9 inches  long,  power  20  diameters,  wiih  stadia, 
vertical  circle  to  5 minutes,  level  on  telescope,  and  clamp  and  tangent, 

mounted  on  column  as  in  Engraving,  Fig.  54  ... . 70  00 

Total $130  00 

93. — Plane  Table,  with  board,  etc.,  like  No.  90 $45  00 

Combined  compass  and  levels 15  00 

Alidade  with  telescope  11  inches  long,  with  stadia,  4|-inch  vertical  cir- 
cle on  silver  to  1 minute,  level  on  telescope,  and  clamp  and  tangent, 

on  column,  power  of  telescope  24  diameters,  Fig.  58 90  00 

Total .'..$150  00 


96. — Set  of  three  leveling  screws  for  any  of  the  above  named  Plane  Tables, 


extra 10  00 

97. — Clamp  and  tangent,  for  movement  in  azimuth,  extra 10  00 


SOLAR  COMPASS. 

100.— Burt’s  Solar  Compass,  with  leveling  adopter,  compound  tangent  ball. 

and  leveling  tripod,  Fig.  25 $210  00 

Note.— For  Pocket  Solar  Compass,  see  No.  140,  and  Fig.  33. 


8 W.  & L.  E.  GURLEY,  TROY.  N.  Y. 

RAILROAD  COMPASSES. 

No.  Price 

105. — 5|-inch  needle,  one  vernier  to  limb,  jacob-staff  mountings,  bras^cover 

and  out-keeper $60  CO 

106. — 5-inch  needle,  two  verniers  to  limb,  do  do  TO  00 

107. — 5^-inch  needle,  do  do  do  Fig.  29  75  00 

VERNIER  COMPASSES. 

110.  — 4-inch  needle,  jacob-staff  mountings,  brass  cover  and  out-keeper $30  00 

111. — 5-inch  needle,  do  do  do  35  00 

112. — 6-inch  needle,  do  do  do  Fig.  30  40  00 

PLAIN  COMPASSES. 

115. — 4-inch  needle,  jacob-staff  mountings,  brass  cover  and  out-keeper $25  00 

116. —  5-inch  needle,  do  do  do  30  00 

117. — 6-inch  needle,  \ do  do  do  Fig.  31  35  00 

EXTRAS  TO  COMPASSES. 

120. — Compass  Tripod,  cherry  legs $5  00 

121.  — Patent  Extension  Tripod,  furnished  with  any  compass 10  00 

122.  — Compass  Tripod,  with  leveling  screws,  and  clamp  and  tangeut  move- 

ment  18  00 

123.  — Compass  Tripod  Mountings,  without  legs 4 00 

124. — Compound  Tangent  Ball,  Fig.  24  6 00 

126. —Leveling  adopter,  large  size,  Fig.  27,  a 7 00 

TELESCOPIC  SIGHT. 

ATTACHABLE  TO  COMPASS  SIGHT.  (See Figs.  28,32,35.) 

Patented  July  9 , 1878. 

130. — Nine-inch  Achromatic  Telescope,  power  about  10  diameters $12  00 

131. — Nine-inch  Achromatic  Telescope,  larger  diameter  of  object  glass  and 

power  about  20  diameters,  Fig.  32 17  00 

132. — Same  Telescope  as  No.  131,  but  furnished  with  micrometer  or  stadia 

wires  for  measuring  distances 20  00 

We  add  to  any  Telescopic  Sight  the  following  extras,  at  prices  annexed : 

133. — Vertical  Circle,  Vernier  to  5' 5 00 

134. — Level  on  Telescope 5 00 

135. — Clamp  and  Tangent  to  Axis  of  Telescope 5 00 


W.  & L.  E.  GUKLEY,  TBOY,  N.  Y.  9 

POCKET  SOLAR  COMPASS.  (Fig. 33.) 

No.  Price 

140.  — Pocket  Solar  Compass,  with  staff  mountings  and  mahogany  box $100  00 

141. — Side  Telescope  and  counterpoise  fitted  to  Pocket  Solar  Compass 25  00 

Note— When  desired,  we  add  to  the  side  telescope,  extras  Nos.  133, 

134,  and  135,  at  prices  named. 

142. — Leather  case  with  shoulder  strap  for  Pocket  Solar  Compass 5 00 

Tripods  for  Pocket  Solar  Compass,  extra,  at  prices  quoted  for  Nos. 

168, 169,  and  170. 

148.— Simple  Dial  Compass,  with  removable  hour  arc,  graduated  for  any  lati- 
tude as  ordered,  two  levels  and  clinometer,  Fig.  41  16  00 


POCKET  COMPASSES,  AND  EXTRAS. 

150. — With  folding  sights,  24-inch  needle,  very  serviceable  for  retracing  lines 


once  surveyed $8  00 

151. — Same  as  above,  with  jacob-staff  mountings,  Fig.  38 10  00 

152.  — With  34-mch  needle,  and  jacob-staff  mountings,  do 12  00 

153. — Same  as  above,  and  two  levels 13  50 

154  —Same  as  152,  but  without  jacob-staff  mountings 10  00 

155. _Vernier  Pocket  Compass,  with  folding  sights,  staff  mountings,  two 

levels,  and  34-inch  needle,  Fig.  36  16  00 

156. -  Same  as  above,  44-inch  needle,  do  18  00 

157.  — Railroad  Pocket  Compass,  with  folding  sights,  staff  mountings,  two 

levels,  3| -inch  needle,  with  limb  reading  to  five  minutes 23  00 

158. — Railroad  Pocket  Compass,  44-inch  needle,  clamp  and  tangent  to  limb, 

with  limb  reading  to  one  minute 28  00 

159. — Railroad  Pocket  Compass,  one  vernier  to  limb,  Fig.  34  40  00 


159A.— Railroad  Pocket  Compass,  44-inch  needle,  clamp  and  tangent  to  limb, 
with  limb  reading  to  one  minute,  with  clamp  and  tangent  to  the  main 
spindle  or  socket,  and  fitted  with  our  new  telescopic  sight  No.  130, 
with  the  extras  of  level,  vertical  circle  to  5',  and  clamp  and  tangent  to 
axis  of  telescope Price  including  tripod  65  00 


159B.— Same  as  above,  but  with  telescopic  sight  No.  131,  Fig.  35  70  00 

159C. — do  do  do  No.  132 73  00 


160. — Vernier  Pocket  Compass,  44-inch  needle,  with  clamp  and  tangent  to 
the  main  spindle  or  socket,  and  fitted  with  our  new  telescopic  sight 
No.  130,  with  the  extras  of  level,  vertical  circle  to  5',  and  clamp  and 
tangent  to  axis  of  telescope . . .Price  including  tripod  55  00 


161. — Same  as  above,  but  with  telescopic  sight  No.  131,  Fig.  37  60  00 

162. —  do  do  do  No.  132  63  00 

167. — Leather  case  with  shoulder  strap  for  pocket  compasses 2 00  to  5 00 

168. — Tripod  for  pocket  compass 5 00 

169. — Tripod  for  pocket  compass,  with  leveling  plates  and  clamp  and  tangent  15  00 

170. — Patent  extension  tripod  for  pocket  compass 10  00 

171. — Tangent  movement  for  ball  spindle  of  pocket  compasses  Nos.  151  to  159  5 00 

172. — Rack  movement  to  vernier  of  Vernier  Pocket  Compass  4 00 

173. — Leveling  adopter,  small  size,  Fig.  64  5 00 


10 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 

MINER’S  COMPASSES  OR  DIPPING  NEEDLES. 

FOR  TRACING  VEINS  OF  MAGNETIC  IRON  ORE, 

No.  Price 

118.—  3-inch  needle,  glass  on  both  sides,  wood  box,  stop  to  needle.  Fig.  39. . . $12  00 

179. —  do  do  do  brass  covers,  stop  to  needle 12 

180. —  do  do  one  side,  brass  cover,  stop  to  needle 12 

181.  — “ Norwegian  Needle,”  glass  on  both  sides,  brass  covers,  3-incb  needle, 

superior  article,  Fig.  40 12 

182. — Same  as  above,  4-inch  needle 15 

The  first  three  of  the  Miners’  Compasses  furnished  without  stop  (each)  10 
Note.-  No  instrument  made  that  will  indicate  the  presence  of  gold  or 
silver. 

LOCKE’S  HAND  LEVEL 

185. — Bronze,  inbox,  Fig.  59 $9 

186. — Nickel  plated,  in  box,  Fig.  59 10 

ABNEY  LEVEL  AND  CLINOMETER. 

187. — This  is  an  improved  ‘‘Locke’s  Hand  Level,”  giving  angles  of  elevation, 

and  is  also  divided  for  slopes,  as  1 to  1,  2 to  1,  etc.,  in  case,  Fig.  60. . . $15 

188.  — Clinometer,  or  Slope  Level,  to  1 deg.,  7 inches  long,  in  walnut  case 8 

189.  — Ditto  (Gunner’s  quadrant  pattern),  with  vernier  to  5 min.,  18  inches 

long,  in  walnut  case 15 

LEVELING  RODS. 

190. — Architects’  Rod,  5|  ft.  closed,  sliding  to  10  ft.,  Fig.  53 $6 

191. — Troy  Rod,  6^  ft.  closed,  sliding  to  12  ft.,  Fig.  51 10 

192. — Boston  Rod,  6 ft.  closed,  sliding  to  11  ft.,  Fig.  49 16 

193.  -Philadelphia  Rod,  7T35  ft.  closed,  sliding  to  13  ft.,  Fig.  48 16 

194. — Philadelphia  Metric  Rod,  2*  metres  closed,  sliding  to  3T7b  metres 16 

195. — New  York  Rod,  6/o  ft.  closed,  sliding  to  12  ft. , Fig.  50 16 

196. —  do  in  3 parts,  either  5 ft.  closed,  sliding  to  13  ft.,  or  5T%  ft. 

closed,  sliding  to  14£  ft.,  Fig.  52 18 

197.  — do  in  4 parts,  5 ft.  closed,  sliding  to  16  ft 20 

198  —New  York  Metric  Rod,  2^  metres  closed,  sliding  to  3T6„  metres 16 

199. — Telemeter,  or  Stadia  Rod,  6 ft.  folded,  unfolding  to  12  ft 12 

200. — English  Rod,  telescope  pattern,  5 ft.  long,  sliding  to  14  ft.,  Fig.  53A  . . 24 


FLAG  STAFFS,  ETC. 

210—6  feet  long,  with  steel-pointed  shoe,  and  divided  off  in  feet,  which  are 
painted  red  and  white,  alternately  

211. — 8 feet  long,  do  do  do 

212. — 10  feet  long,  do  do  do 

215.— Rod  level  for  plumbing  a rod  or  flag  staff 5 


88  888  88  88  8 888888  88888  SPSS 


W.  & L.  E.  GURLEY,  TROY,  H.  Y.  11 

CHAINS. 

No.  Price 

220.—  66  feet,  100  links,  with  oval  rings,  No.  8 refined  iron  wire . . $4 


220.—  66  feet,  100  links,  with  oval  rings,  No.  8 refined  iron  wire . . $4 


221. 

— 66 

do 

100 

do 

do 

10 

do  

3 50 

222. 

— 33 

do 

50 

do 

do 

8 

do  

2 50 

223. 

- 33 

do 

50 

do 

do 

10 

do  

2 25 

224. 

—100 

do 

100 

do 

do 

8 best  steel  wire 

10  00 

225. 

—100 

do 

100 

do 

do 

10 

do  

8 50 

226. 

— 50 

do 

50 

do 

do 

8 

do  

5 50 

227. 

— 50 

do 

50 

do 

do 

10 

do  - 

4 75 

228. 

— 66 

do 

100 

do 

do 

8 

do  

9 00 

229. 

— 66 

do 

100 

do 

do 

10 

do  

7 00 

230. 

- 33 

do 

50 

do 

do 

8 

do  

5 00 

231. 

- 33 

do 

50 

do 

do 

10 

do 

4 00 

STEEL 

BRAZED 

CHAINS. 

235. 

—100  feet. 

, 100  links,  No.  12  steel,  spring  temper,  brazed  links  and  rings. 

$11  50 

236. 

— 66 

do 

100 

do 

do 

do 

10  00 

237. 

- 50 

do 

50 

do 

do 

do 

6 00 

238. 

- 33 

do 

50 

do 

do 

do 

5 50 

The  sale  of  our  steel  brazed  chains  is  constantly  increasing,  and  they 
displace  the  ordinary  chains  wherever  they  are  tried,  on  account  of 
superior  lightness  and  strength.  They  are  practically  the  only 
chains  now  used  in  railroad  construction. 

Pennsylvania  chains  of  2 and  4 poles  with  40  and  80  links,  same  price 
as  chains  of  50  and  100  links. 

SPANISH  VARA  AND  FRENCH  METRE  CHAINS. 

FOR  USE  IN  TEXAS,  MEXICO,  SOUTH  AMERICA,  AND  CUBA. 


240  —10  varas  or  10  metres,  50  links,  No.  10  refined  iron  wire $2 

241. -20  do  20  do  100  do  10  do  3 

242. — 10  do  10  do  50  do  8 do  2 

243. -20  do  20  do  100  do  8 do  4 

244. — 10  do  10  do  50  do  10  best  steel  wire 4 

245. -20  do  20  do  100  do  10  do  7 

246. — 10  do  10  do  50  do  8 do  5 00 

247. — 20  do  20  do  100  do  8 do  9 00 

248. — 10  do  10  do  50  links,  brazed  links  and  rings  No.  12  steel 

wire,  tempered 5 50 

249. — 20  do  20  do  100  do  do  12  do  10  00 


Note.— Parties  ordering  chains  Nos.  240  to  249,  must  state  whether 
vara  or  metre  chains  are  wanted. 

Steel  snaps  to  make  full  chains  into  “half  chains,”  no  extra  charge, 
if  ordered  with  the  chain. 


8 8 8 8 S S S i?  g 8 8 8 8888  888888 


12  W.  & L.  E.  GURLEY,  TROY,  N.  Y. 

GRUMMAN  PATENT  STEEL  CHAINS. 

No.  Pkice 

260. —  66  feet,  No.  15  tempered  steel  wire,  100  links,  weight  1^  lbs $9  00 

With  10  extra  links. 

261. —  33  do  do  50  do  | lb 5 00 

With  5 extra  links. 

262. -100  do  do  200  do  2 lbs 11  50 

With  15  extra  links. 

263. —  50  do  do  100  do  1 lb 6 00 

With  10  extra  links. 

264. —  33  feet,  No.  12  wire,  5 tallies,  with  5 extra  links,  1}§  lbs 5 50 

265. —  66  do  10  do  10  do  3 lbs 10  00 

268. — 50  do  5 do  5 do  2^  lbs. 6 00 

267.— 100  do  10  do  10  do  4*  lbs 11  50 

263.—  50  feet,  No.  18  tempered  steel  wire,  100  links,  with  attachments  of 

spring-balance,  level,  and  thermometer,  for  very  accurate  measure- 
ments ; weight  £ lb. . 15  00 

270. — Brass  Plummet,  to  use  with  light  chain 2 00 

271. — Spring-balance  to  use  with  chains  Nos.  260  to  263 2 00 

MARKING  PINS. 

275. — Set  of  11  Pins,  iron  wire,  No.  4 $1  50 

276. —  do  steel  wire,  No.  6 2 00 

277.  — do  brass  wire,  No.  4 3 00 

278. —  do  steel  wire,  loaded 3 00 

279. —  do  steel  wire,  very  light,  with  leather  case 2 00 

280.  — Timber  scribes  or  Marking  irons,  each 1 25 

CHESTERMAN’S  METALLIC  TAPE  MEASURES. 

These  tapes  are  made  of  linen  thread,  interwoven  with  fine  brass  wire, 
not  so  liable  to  stretch  as  the  usual  linen  tape,  and  better  calculated 
to  withstand  the  effects  of  moisture.  They  are  in  substantial 
leather  cases. 

285.— Metallic  tape  measures,  33  feet  long,  in  lOths  or  12ths,  each $2  35 

287. —  do  50  do  do  3 00 

288. —  do  66  do  do  3 30 

292.—  do  100  do  do  4 75 

CHESTERMAN’S  METALLIC  TAPES  WITHOUT  BOXES. 

295.  — Chesterman’s  metallic  tapes,  without  box,  50  feet,  lOths  or  12ths.  ..  $1  75 

296. —  do  do  66  do  2 25 

297. —  do  do  100  do  ....  3 25 

Note.— We  can  furnish  Nos.  285  to  297  of  any  intermediate  lengths  required. 


W.  & L.  E.  GURLEY,  TROY,  N.  Y.  13 

CHESTERMAN’S  STANDARD  STEEL  TAPE  MEASURES. 

Steel  tape  measures ; all  steel,  to  wind  up  in  a box,  same  as  linen 
measures,  the  most  accurate,  durable  and  portable  measures. 

No.  Price 

300.— Steel  tape  measure,  10  feet  long,  in  lOths  or  12ths,  in  German  silver 

case,  each $3  50 

SQl.—gteel  tape  measure,  10  feet  long,  tape  divided  on  one  side  to  12ths,  and 

on  the  other  to  centimeters  and  millimeters 3 75 

302.— Steel  tape  measure,  25  feet  long,  in  lOths  or  12ths  each 5 75 

303  — do  33  do  do  6 25 

305. —  do  50  do  do  8 50 

306. —  do  66  do  do  11  00 

307. —  do  75  do  do  12  50 

308. —  do  100  do  do  16  00 

309.  — do  50  do  do  extra  wide  and  heavy  13  00 

POCKET  STEEL  TAPE  MEASURES. 

315. — Pocket  Steel  tapes,  in  German  silver  cases,  with  spring  and  stop, 

divided  in  lOths  or  12ths  of  feet,  3 feet  long $1  35 

316. —  do  do  do  4 do  1 50 

317. —  do  do  do  5 do  1 75 

318. —  do  do  do  6 do  2 00 

319. —  do  do  do  8 do  2 25 

320. —  do  do  do  12  do  3 00 

These  pocket  tapes,  with  divisions  to  centimetres  and  millimetres  on 
the  other  side,  25  to  59  cents  per  tape  higher,  according  to  length. 

PAINE’S  PATENT  STANDARD  STEEL  TAPES. 

IN  LEATHER  CASES,  FLUSH  HANDLES. 

325. — Steel  tape  measure,  33  feet  long,  lOths  or  12ths  $5  50 

326. —  do  50  do  do  8 00 

327. —  do  66  do  do  10  00 

328. —  do  75  do  do  12  00 

329. —  do  100  do  do  15  00 

339. —  do  in  japanned  case,  25  feet  long,  lOths  or  12ths  3 50 

331. —  do  do  33  do  do  4 50 

332. —  do  do  50  do  do  6 00 

333. —  do  do  66  do  do  8 00 

334. —  do  do  75  do  do  10  00 

335. —  do  do  100  do  do  12  00 

Tapes  Nos.  325  to  335,  without  cases,  10  cts.  per  foot. 

Tapes  Nos.  325  to  335,  with  metric  measure  on  reverse  side,  at  an  extra 
cost  of  5 cts.  per  foot. 

EXTRAS  TO  PAINE’S  PAT.  STAND.  STEEL  TAPES. 

340. — Handles,  with  graduated  scale,  per  pair  $4  00 

341.  — Pocket  thermometers 1 50 

342.  — Spring  balance  and  level 4 00 


14 


W.  & L.  E.  GUBLEY,  TBOY,  N.  Y. 


STANDARD  STEEL  RIBBONS. 

Our  own  manufacture,  without  joint,  for  testing  chains  or  tapes,  or  for  bridge  work. 
Ribbon,  f to  \ inch  wide,  graduated  on  soldered  brass  plates. 


No.  Price 

345. — Steel  Ribbon,  33  feet  long,  with  handles  and  reel $3  00 

346. —  do  50  do  do  4 00 

347. —  do  66  do  do  6 00 

348. —  do  100  do  do  7 00 


Nos.  345  and  347  are  graduated  each  foot  up  to  ten  feet,  and  also  at  each 
sixteen  and  one-half  feet. 

Nos.  346  and  348  are  gratuated  each  foot  up  to  ten  feet,  and  at  each  ten 
feet  thereafter. 

Longer  tapes  to  order. 


NEW  ADJUSTABLE  PLUMB  BOBS. 

This  plummet  has  a concealed  reel,  around  which  the 
string  is  wound  by  turning  the  milled  head  on  top.  The 
friction  upon  the  reel  within  will  hold  the  bob  at  any  de- 
sired point  of  the  line. 


No.  Price 

350.— 10  oz $2  50 

354.— 30  oz 5 00 


BRASS  PLUMB  BOBS. 


355.— Steel  point,  screw  head,  3 oz $1  00 

358.-  do  do  6 oz 125 

357. —  do  do  10  oz 150 

358. —  do  do  14  oz 2 00 

359. —  do  do  20  oz. 2 50 

360. —  do  do  24  oz 3 00 

361. —  do  do  32  oz 3 50 


ODOMETERS. 


FOR  MEASURING  DISTANCES  BY  THE  REVOLUTION  OF  A 
CARRIAGE  WHEEL. 

No.  Price 

365. — Odometer.  Fig.  63,  outside  dial,  with  bolts  for  attaching,  complete  — $10  00 

366. — Odometer,  Fig.  61,  inside  dial,  with  leather  case  and  straps 15  00 


15 


W.  & L.  E.  GURLEY,  TROY,  BT.  Y. 

ANEROID  BAROMETERS. 

FOR  ASCERTAINING  HEIGHTS,  DIFFERENCES  OF  LEVEL  AND  METEOR- 
OLOGICAL CHANGES,  APPROACH  OF  STORMS,  ETC. 

370. — Mountain  Aneroid  Barometers,  compensated  for  temperature,  with 
silvered  dials,  in  morocco  cases,  accompanied  by  a hand-book  of 
instructions. 

These  instruments  as  now  made  are  nearly  as  portable  as  an  ordinary 
watch,  and  yet  are  fully  as  accurate  as  the  larger  sizes.  They  are  of 
very  great  service  to  the  engineer  and  tourist,  as  well  as  to  the  scien- 
tific observer,  and  are  rapidly  coming  into  general  use. 

A. — Pocket  Aneroid,  1—incli  dial,  altitude  scale  to  8000  feet  $18  00 


B.— 

do 

do 

do 

10000  feet 

20  00 

C.— 

do 

do 

do 

15000  feet 

25  00 

D.— 

do 

do 

do 

20000  feet 

27  00 

E.— 

do 

do 

do 

15000  feet,  and  thermometer 

27  00 

H.— Pocket  Aneroid,  l|-inch  dial,  altitude  scale  to  10000  feet,  and  opposite 


side  with  pocket  compass  and  thermometer $28  00 

K.— Pocket  Aneroid,  2f-inch  dial,  altitude  scale  to  3000  feet 19  00 

L-—  do  do  do  5000  feet 19  00 

M. —  do  do  do  8000  feet 20  00 

N. —  do  do  do  10000  feet 22  00 

O.  - do  do  do  15000  feet 25  00 

P—  do  do  do  20000  feet • 27  QO 


16  W.  & L.  E.  GURLEY,  TROY,  N.  Y. 

ANEROID  BAROMETERS.—  Concluded. 

No.  Price 

Q. — Pocket  Aneroid,  2f-inch  dial,  altitude  scale  to  10000  ft.,  and  thermometer  $24  00 

R. —  do  do  do  15000  ft.,  do  27  00 

S. — Government  Pattern  Aneroid,  4±-mch  dial,  altitude  scale  to  4000  feet,  and 

thermometer,  with  leather  case  and  strap 33  00 

T. —  do  do  hut  with  altitude  scale  to  8000  feet 35  00 

U. —  do  do  do  do  10000  feet 36  00 

V. —  do  do  do  do  15000  feet 38  00 

W. —  do  do  do  do  20000  feet 40  00 

X. — Plain  Aneroid,  no  altitude  scale,  5-inch  dial,  with  thermometer  and 

open  face  to  show  mechanism,  for  parlor  use 20  00 

Y. —  do  but  with  6^-inch  dial 25  00 

Note.— The  barometers  described  above  are  the  most  desirable  styles. 

We  can,  however,  furnish  any  of  the  styles  mentioned  in  the  cata- 
logues of  other  dealers,  at  their  list  prices. 

A Treatise  on  the  Aneroid  Barometer ; its  construction  and  use. 
Illustrated 50 

PRICES  FOR  PARTS  OF  INSTRUMENTS  LIABLE  TO 
LOSS  OR  INJURY. 

FOR  TRANSITS. 

Needle  and  centre  pin $2  50 

Ground  glass  level  vial  for  plate  or  standard,  each 50 

do  do  brass  mounted  complete,  for  plate  or  standard,  each.  2 50 

do  do  for  telescope,  each 150 

Cap  for  eye-piece  or  object-glass,  each 75 

Shade  for  object-glass 75 

Clamp  screws  for  horizontal  limb,  each 75 

Tangent  screw  for  leveling  head 1 50 

Clamp  do  do  75 

Leveling  do  do  each * 1 50 

Eye-piece  complete 6 00 

Object-glass  complete 6 00 

Platina  cross-wires  and  diaphragm 3 00 

do  stadia  do  do  5 00 

FOR  Y LEVELS. 

Ground  glass  level  vial $2  00 

Cap  for  eye-piece  or  object-glass,  each 75 

Clamp  screw  for  leveling  head ...  75 

Tangent  do  do  1 50 

Leveling  do  do  each 1 50 

Eye -piece  complete 6 00 

Object-glass  complete. . 7 00 

Platina  cross-wires  and  diaphragm 3 00 

do  stadia  do  do  5 00 


W.  & L.  E.  GURLEY,  TROY,  N.  Y.  17 

FOR  SURVEYORS’  COMPASSES. 

Price 

Needle  and  centre  pin $2  50 

Plain  glass  level  vials,  each 25 

do  do  brass  mounted  complete 2 00 

Brass  cover  for  compass  of  our  make 1 00 

Outkeeper 1 00 

Staff  mountings,  brass  head 2 50 

do  steel  point 60 

Ball-spindle 1 50 

Compass  sight  vanes,  each 2 50 

Clamp  screw  for  spindle  or  sight  vane 75 

Tangent  screw  for  moving  vernier 1 50 

Staff  mountings  complete  for  pocket  compass . 2 50  to  3 50 

MISCELLANEOUS. 

Patent  Extension  Tripod,  Fig.  17,  for  Transit  or  Level  $15  00 

Extension  legs  only,  with  clamps,  do  do  per  set 10  00 

Plain  Mahogany  Tripod,  do  do  10  00 

Mahogany  tripod  legs  only,  do  do  per  set  5 00 

Wooden  cap,  with  brass  screw  plate,  for  tripod  head 1 00 

Ring  for  tripod  legs 25 

Brass  bolts  do  each  50 

Metal  points  do  do  50 

Screw  drivers,  each 25 

Steel  adjusting  pins,  each 10 

Brass  wrench  for  centre  pin 10 

Glass  circle  for  compass  face 25 

Mahogany  case  with  lock  and  key  and  leather  strap,  fitted  complete  for 

Transit  or  Level  0 00 

do  do  do  for  Compass 5 00 

Regraduating  compass  circle  5 00 

do  horizontal  limb  and  verniers  of  Transit 10  00 

dp  vertical  do  do  5 00 

Reading  microscope 75 

Plumb-bob  for  Transit  or  Level  1 50 

Target  for  New  York  or  Philadelphia  Rod 5 50 

Clamp  for  New  York  Rod 2 50 

Rubber  hood  for  Transit  or  Level 1 00 

Chamois  skin,  best  quality 65 

Chain  handles  each * ’ 75 

Chain  tallies,  per  set  of  nine 50 


SPECIAL  NOTICE. 


Many  of  our  smaller  instruments,  such  as  pocket 
compasses,  chains,  tapes,  small  packages  of  paper 
and  parts  of  large  instruments,  can  be  sent  by  mail 
securely  packed,  and  at  much  lower  rates  than  are 
charged  by  express  companies. 

In  all  cases  where  goods  are  to  be  sent  by  mail, 
the  cash  for  postage  as  well  as  for  the  goods  must 
accompany  the  order.  All  articles  forwarded  by 
mail  are  at  purchaser’s  risk. 

Price  List  of  all  our  Drawing  Instruments,  Draw- 
ing Materials,  and  Books— a fully  Illustrated  Cata- 
logue of  one  hundred  pages— sent  to  any  address 
postpaid,  on  application. 

Samples  of  drawing  paper,  tracing  paper,  tracing 
cloth,  and  profile  and  cross-section  papers  sent  with 
prices  on  application. 

For  the  convenience  of  our  customers,  we  will 
furnish  any  articles  not  on  our  list,  but  described 
in  the  catalogue  of  any  American  manufacturer  or 
dealer  in  mathematical  or  optical  instruments,  at 
catalogue  prices, 


INFORMATION  TO  PURCHASERS, 


Selection  of  Instruments. — Where  only  original  surveys  or 
the  bearing  of  lines  in  the  preparation  of  County  Maps  is  required  the 
Plain  Compasses  will  answer. 

The  Vernier  Compass,  or  Vernier  Transit  Compass,  will  be  required 
where  the  variation  of  the  needle  is  to  be  allowed,  as  in  retracing  the 
lines  of  an  old  survey,  etc. 

When  in  addition  to  the  variation  of  the  needle  local  attraction 
must  be  taken  into  account,  and  the  angles  taken  independently  of 
the  needle,  an  instrument  with  a divided  limb  must  be  employed,  and 
for  this  purpose  the  Railroad  Compass  will  be  sufficient. 

For  a mixed  practice  of  general  surveying,  including  farm  and  city 
work,  the  establishment  of  grades  of  roads,  the  running  of  levels,  etc., 
such  an  instrument  as  the  Surveyors’  Transit,  with  its  various  attach- 
ments, is  amply  sufficient. 

The  various  forms  of  the  Engineers’  Transit,  the  Mountain  Transit, 
and  the  Y Leveling  Instruments,  are  designed  for  Engineering  of  the 
highest  class. 

In  the  U.  S.  public  land  surveys,  an  instrument  with  Solar  appara- 
tus is  required,  and  the  Solar  Compass  is  usually  selected. 

In  surveys  of  Mining  Claims,  especially  in  the  high  elevations  of 
Colorado,  and  for  the  surveys  of  mines  in  general,  the  Mountain 
Transit,  either  with  the  Solar  Attachment  or  with  other  extras,  has 
proved  an  almost  universal  favorite. 

The  new  Drainage  Level  is,  we  believe,  the  most  simple  and  effi- 
cient instrument  designed  for  the  drainage  of  farms,  etc. 

The  Architects’  Level  is  employed  in  laying  out  buildings,  deter- 
mining the  level  of  their  floors,  sills,  windows,  and  the  general  work 
of  the  builder: 

The  various  forms  of  the  Pocket  Compass  and  Pocket  Solar  Com- 
pass, with  or  without  Telescopic  Attachments,  are  very  desirable  for 
a large  class  of  work  where  extreme  lightness  and  portability  are 
demanded. 

Where  iron  ores  are  also  to  be  traced,  the  Miners’  or  Dip  Compass, 
and  the  Dial  Compass  are  often  required. 

We  do  not  pretend  to  make  any  instrument  by  which  veins  of  gold 
and  silver  can  be  traced,  or  the  presence  of  those  metals  detected. 


20 


INFORMATION  TO  PURCHASERS. 


Our  instruments  are  not  for  sale  by  dealers  in  books  and  apparatus ; 
we  do  not  deem  it  advisable  to  add  to  our  prices  to  enable  us  to  give 
such  dealers  a large  discount , which  of  course  would  be  paid  by  the 
purchaser. 

Warranty. — All  our  instruments  are  examined  and  tested  by  us 
in  person,  and  are  sent  to  the  purchaser  adjusted  and  ready  for  imme- 
diate use. 

They  are  warranted  correct  in  all  their  parts — we  agreeing  in  the 
event  of  any  defect  appearing  after  reasonable  use,  to  repair  or  replace 
with  a new  and  perfect  instrument,  promptly  and  at  our  own  cost, 
express  charges  included,  or  we  will  refund  the  money  and  the 
express  charges  paid  by  the  customer. 

Instances  may  sometimes  occur,  in  a business  as  large  and  widely 
extended  as  ours,  where,  owing  to  careless  transportation,  or  to  de- 
fects escaping  the  closest  scrutiny  of  the  maker,  instruments  may 
reach  our  customers  in  bad  condition.  We  consider  the  retention  of 
such  instruments  in  all  cases  an  injury  very  much  greater  to  us  than 
to  the  customer  himself. 

Trial  of  Instruments. — It  may  often  happen  that  this  state- 
ment of  the  prices  and  quality  of  our  instruments  may  come  into  the 
hands  of  those  who  are  entirely  unacquainted  with  us,  or  with  the 
quality  of  our  work,  and  who  therefore  feel  unwilling  to  make  a final 
purchase  of  an  article,  of  the  excellence  of  which  they  are  not  per- 
fectly assured. 

To  such  we  make  the  following  proposition:  We  will  send  the 
instrument  to  the  express  station  nearest  the  person  giving  the  order, 
and  direct  the  express  agent,  on  delivery  of  the  same,  to  collect  our 
bill,  together  with  charges  of  transportation,  and  hold  the  money  on 
deposit  until  the  purchaser  shall  have  had,  say  two  weeks,  actual  trial 
of  its  quality. 

If  not  found  as  represented,  he  may  return  the  instrument  before 
the  expiration  of  that  time,  and  receive  the  money  paid,  in  full, 
including  express  charges,  and  direct  the  instrument  to  be  returned 
to  us. 

Extent  of  our  Business. — The  manufacture  of  surveying  instru- 
ments has  been  conducted  by  us  over  thirty-nine  years,  and  thousands 
of  our  instruments  have  been  distributed  to  customers  in  all  parts  of 
the  United  States  and  Canadas;  in  Cuba,  South  America,  Sandwich 
Islands,  and  Japan. 

i Our  facilities  for  manufacturing,  which  for  many  years  have  been 


INFORMATION  TO  PURCHASERS. 


21 


far  superior  to  those  of  any  other  similar  establishment,  we  have  now 
(1884)  greatly  increased  by  the  introduction  of  new  machinery  and 
tools  of  the  most  improved  construction.  Our  manufactory  has  been 
rebuilt  of  nearly  three  times  its  former  size,  and  we  are  better  pre- 
pared than  ever  before  to  till  orders  for  any  of  our  instruments  with 
promptness  and  satisfaction. 

Low  Prices  of  our  Instruments. — It  is  often  urged  by  other 
makers,  and  persons  prejudiced  in  their  favor,  that  it  is  impossible  to 
make  first-rate  instruments  at  the  prices  charged  by  us,  and  which 
are  so  very  far  below  those  of  other  skillful  manufacturers. 

We  have  only  to  reply,  in  addition  to  what  we  have  stated  in  our 
warranty,  that  a visit  to  our  works,  and  a comparison  of  our  facilities 
with  those  of  our  competitors,  would  dispel  all  questions  as  to  our 
ability  to  surpass  them,  not  only  in  the  cheapness,  but  also  in  the 
superior  quality  of  our  work. 

Packing,  Etc. — Each  of  our  Transits,  Levels,  and  Surveyors’  Com- 
passes, is  packed  in  a well -finished  mahogany  case,  furnished  with 
lock  and  key  and  brass  hooks,  and  leather  strap  for  convenience  in 
carrying.  Each  case  is  provided  with  screw-drivers,  adjusting  pin, 
and  wrench  for  centre  pin,  and,  if  accompanied  by  a tripod,  with  a 
brass  plumb-bob  ; with  all  instruments  for  taking  angles;  without  the 
needle,  a reading  microscope  is  also  furnished. 

Unless  the  purchaser  is  already  supplied,  each  instrument  is  accom- 
panied by  our  “ Manual,”  giving  full  instructions  for  such  adjustments 
and  repairs  as  are  possible  to  one  not  provided  with  the  facilities  of 
an  instrument  maker. 

When  sent  to  the  purchaser,  the  mahogany  cases  are  carefully  en- 
closed in  outside  packing  boxes,  of  pine,  made  a little  larger  on  all 
sides  to  allow  the  introduction  of  elastic  material,  and  so  effectually 
are  our  instruments  protected  by  these  precautions,  that  of  many 
thousand  sent  out  by  us  during  the  last  thirty-nine  years,  in  all 
seasons,  by  every  mode  of  transportation,  and  to  all  parts  of  the 
Union  and  the  Canadas,  and  to  Foreign  Countries,  not  more  than 
three  or  four  have  sustained  any  serious  injury. 

Instruments  packed  for  Foreign  shipment,  are  hermetically  sealed 
in  tin  cases. 

Means  of  Transportation. — Instruments  can  be  sent  by  express 
to  almost  every  town  in  the  United  States  and  Canadas,  regular 
agents  being  located  at  all  the  more  important  points,  by  whom  they 
are  forwarded  to  smaller  places  by  stage.  The  charges  of  transporta- 


22 


INFORMATION  TO  PURCHASERS. 


tion  from  Troy  to  the  purchaser  are  in  all  cases  to  he  borne  by  him, 
we  guaranteeing  the  safe  arrival  of  our  instruments  to  the  extent  of 
express  transportation,  and  holding  the  express  companies  responsible 
to  us  for  all  losses  and  damages  on  the  way. 

Finish  of  Instruments. — Customers  ordering  instruments,  will 
do  us  a favor  by  mentioning  whether  they  prefer  them  of  bright  or 
bronze  finish,  the  cost  being  the  same  in  either  case. 

If  no  direction  is  given,  we  usually  send  Transit  and  Leveling 
instruments  of  bronze  finish,  and  Compasses  of  bright  finish. 

Terms  of  Payment  are  uniformly  cash,  and  we  have  but  one 
price,  whether  ordered  in  person  or  by  mail.  Our  terms  are  as  low  as 
we  think  instruments  of  equal  quality  can  be  made,  and  will  not  be 
varied  from  the  list  given  on  the  previous  pages. 

Remittances  may  be  made  by  a draft,  payable  to  our  order  at  Troy, 
Albany,  New  York,  Bcston  or  Philadelphia,  which  can  be  procured 
from  banks  or  bankers  in  almost  all  the  larger  villages,  or  by  post- 
office  money  order,  or  by  registered  mail. 

These  may  be  sent  by  mail  with  the  order  for  the  instrument,  and 
if  lost  or  stolen  on  the  route,  can  be  replaced  by  a duplicate,  obtained 
as  before,  and  without  additional  cost. 

The  customer  may  also  send  the  money  in  advance  through  the 
express  agent,  or,  as  is  most  common,  may  pay  the  agent  on  receipt  of 
the  instrument  in  funds  current  in  New  York  or  Boston. 

The  cost  of  returning  the  money  on  bills  collected  by  express  of 
amounts  under  $20,  will  be  charged  to  the  customer. 

REPAIR  OF  INSTRUMENTS. 

Hundreds  of  instruments  of  our  own  and  others’  make  come  to  us 
every  year  for  refitting  and  repairs,  and  so  much  correspondence 
arises  therefrom,  that  we  are  led  to  believe  that  a brief  statement  in 
this  place  of  the  cost  of  such  repairs,  etc.,  will  be  of  service  to  our 
customers  and  ourselves. 

Most  instruments  sent  to  us  for  repairs  are  injured  by  falls;  many 
are  worn  and  defective  in  parts  after  long  use  ; and  others  are  sent  for 
repolishing  and  renovating. 

We  advise  our  customers  having  instruments  in  need  of  repairs,  etc., 
to  send  them  immediately  to  us,  as  our  facilities  enable  us  to  do  the 
work  much  more  economically  and  promptly  than  any  other  maker, 
however  accessible. 


INFORMATION  TO  PURCHASERS. 


23 


They  should  always,  when  practicable,  be  placed  in  their  own 
boxes,  and  these  enclosed  in  an  outside  packing  case,  an  inch  larger 
in  all  its  dimensions,  that  the  interval  between  the  two  may  be  filled 
with  paper  wadding,  hay  or  fine  shavings. 

A note  specifying  the  repairs  needed,  should  accompany  the  instru- 
ment, and  a letter  should  also  be  sent  by  mail  to  us,  giving  not  only 
directions  as  to  the  repairs,  but  also  stating  when  the  return  of  the 
instrument  is  required,  and  the  precise  location  to  which  it  should  be 
forwarded.  It  should  also  be  remembered  that  each  instrument  is 
made  to  fit  its  own  spindle  and  no  other  ; and  therefore  this  part,  with 
the  parallel  plates  and  leveling  screws,  if  it  has  any,  should  always  be 
sent  with  it. 

The  legs  and  brass  head  in  which  they  are  inserted  need  never  be 
sent,  unless  themselves  in  need  of  repairs. 

Compasses. — These  come  to  us  with  the  plates  sprung,  the  sights 
bent  or  broken,  the  glass  or  level  vials  fractured,  and  the  jfivot  so 
dulled  as  to  render  the  needle  sluggish  and  unreliable.  The  cost  of 
repairing  the  defects  above  named,  ranges  from  $2  to  $8  or  $10.  A 
new  pair  of  sights  fitted  costs  $5  ; a new  needle,  with  jeweled  centre 
and  pivot  complete,  $2.50  ; a new  jeweled  centre,  $1.50  ; regraduating 
compass  circle,  $5.00. 

The  compass  should  always  be  accompanied  by  the  ball  spindle, 
and  if  a new  ball  spindle  is  required,  the  whole  instrument,  or  at  least 
the  socket  in  which  the  spindle  fits,  should  be  sent  with  the  letter  of 
advice  to  us;  a new  ball  spindle  costs  $1.50. 

Transit  Instruments.— The  repairs  of  the  Vernier  Transits  cost 
about  the  same  as  those  of  the  compasses  above  stated. 

The  injuries  sustained  by  the  falls  of  Engineers’  and  Surveyors’ 
Transits  are  usually  much  more  serious  ; in  these  the  plates,  standards 
and  cross-bar  of  telescope  are  often  bent,  and  the  sockets  or  centres 
usually  so  deranged  as  to  he  entirely  useless. 

The  cost  of  repairing  an  instrument  with  such  injuries  ranges 
from  10  to  30,  or  even  50  dollars,  the  new  sockets  alone  costing  from 
15  to  20  dollars. 

Variation  Plate  added  to  any  Engineers’  Transit 

sent  tor  repairs,  costs jMg  qq 

^graduating  horizontal  limb  and  verniers 10  00 

Kegraduating  vertical  limb  and  vernier 5 00 

Platinum  Cross- wires.— None  but  a practised  hand  and  provided 
with  the  best  facilities  can  properly  set  the  platinum  wires  in  a cross- 


24 


INFORMATION  TO  PURCHASERS. 


wire  diaphragm,  and  it  is  useless  therefore  to  send  a parcel  of  wire 
for  that  purpose. 

The  only  way  in  which  they  can  be  replaced  without  sending  the 
telescope  is  to  take  out  the  ring  and  send  it  to  us  with  its  screws, 
washers,  etc.,  and  we  will  return  it  properly  secured. 


The  price  of  platinum  cross-wires,  plain,  replaced 

in  old  ring,  is 

Stadia  wires,  replaced  in  old  ring .... 

If  sent  by  mail,  add  15c.  for  postage  and  registry. 


$2  00 
3 00 


When  it  is  desired  to  substitute  platinum  for  spider-web,  a new 
ring  with  screws,  etc. , will  be  required. 


The  price  of  platinum  cross- wires,  with  diaphragm, 

screws,  etc.,  plain,  is  (see  Fig.  3) $3  00 

Stadia  wires,  with  diaphragm,  etc.  (see  Figs.  4 & 5)  5 00 


Leveling  Instruments  are  generally  much  less  injured  by  falling 
than  Transits,  the  damages  being  included  usually  in  the  bending  of 
the  cross-bar,  the  springing  of  the  sockets,  and  the  breaking  of  the 
level  vial. 

The  cost  of  repairs  varies  from  5 to  15  dollars ; a new  level  vial  set 
in  the  tube  costs  two  dollars. 

Repolishing  Instruments. — The  cost  of  repolishing  an  instru- 
ment, involving  also  of  course  its  complete  renovation  and  adjustment, 
varies  with  the  different  kinds,  but  may  be  stated  generally  as 
follows : 


Compasses,  from $5  to  $10 

Transits,  do  15  to  20 

Levels,  do  12  to  15 


No  additional  charge  is  made  for  bronzing  or  blackening  an  instru- 
ment when  repolished. 

Payment  of  Repairs,  etc.,  may  be  made  at  the  express  office 
where  the  instrument  is  received,  the  customer  paying  for  the  first 
transportation  of  the  instrument  to  us  or  not,  as  he  may  prefer.  When- 
ever the  freight  is  paid  in  advance,  the  express  receipt  should  be 
mailed  immediately  to  us. 

W.  & L.  E GURLEY, 

Mathematical  Instrument  Makers, 

Fulton  St.,  opposite  North  End  of  Union  R.  R.  Depot,  Trot,  N.  Y. 


PREFACE 


TO  THE  TWENTY-FIFTH  EDITION. 


SINCE  the  twenty-third  edition  of  our  Manual  in  1878, 
the  number  and  variety  of  the  instruments  manu- 
factured by  us  have  so  rapidly  increased  as  to  require  that 
the  book  should  be  largely  re-written. 

Our  facilities  for  manufacturing  have  also  greatly  multi- 
plied, and  we  now  occupy  over  twenty  thousand  square  feet 
of  floors  in  a building  constructed  with  special  reference  to 
our  business,  and  equipped  with  a steam-engine  of  eighty 
horse-power  and  the  best  machinery  of  all  kinds.  Among 
these  are  twelve  graduating  engines,  of  which  six  are  auto- 
matic, three  engraving  and  figuring  machines,  over  one 
hundred  lathes,  and  other  tools  too  numerous  to  be  further 
described. 

The  business  which  has  been  conducted  by  us  for  over 
thirty-nine  years,  has  now  become  so  widely  known  that 
our  customers  are  found  all  over  the  civilized  world. 

To  this  ever-widening  circle  of  our  patrons  and  friends 
we  now  commit  this  description  of  our  instruments,  with 
the  hope  that  it  may  be  found -of  increasing  value  and 
interest. 

W.  & L.  E.  GURLEY. 

Troy,  N.  Y.,  January,  1884 


SURVEYORS’  INSTRUMENTS. 


Of  all  the  instruments  used  in  surveying,  the  American 
Transit,  in  its  various  modifications,  is  by  far  the  most 
important,  and  we  shall  therefore  begin  with  that  form 
commonly  known  as  the 

ENGINEERS’  TRANSIT. 


Fig.  1. 

Price  as  shown  above,  with  5-inch  needle  and  tripod,  $150.00. 


28  THE  ENGINEERS*  TRANSIT. 


The  essential  parts  of  the  Transit, 
as  shown  in  the  cut,  are  the  telescope 
with  its  axis  and  two  supports,  the 
circular  plates  with  their  attach- 
ments, the  sockets  upon  which  the 
plates  revolve,  the  leveling  head , and 
the  tripod  on  which  the  whole  instru- 
ment stands. 

The  telescope  is  from  ten  to  eleven 
inches  long,  firmly  secured  to  an 
axis  having  its  bearings  nicely  fitted 
in  the  standards,  and  thus  enabling 
the  telescope  to  be  moved  in  either 
direction,  or  turned  completely 
around  if  desired. 

The  different  parts  of  the  tele- 
scope are  shown  in  Fig.  2. 

The  object-glass  is  composed  of 
two  lenses,  so  as  to  show  objects 
without  color  or  distortion,  is  placed 
at  the  end  of  a slide  having  two 
bearings,  one  at  the  end  of  the  outer 
tube,  the  other  in  the  ring  C C,  sus- 
pended within  the  tube  by  four 
screws,  only  two  of  which  are  shown 
in  the  cut. 

The  object-glass  is  carried  out  or 
in  by  a pinion  working  in  a rack 
attached  to  the  slide,  and  thus  ad- 
justed to  objects  either  near  or 
remote  as  desired. 

The  eye-piece  is  made  up  of  four 
piano  convex  lenses,  which,  begin- 
ning at  the  eye-end,  are  called 


THE  ENGINEERS’  TRANSIT. 


29 


respectively  the  eye,  the  field,  the  amplifying,  and  the 
object  lenses,  the  whole  forming  a compound  microscope 
having  its  focus  in  the  plane  of  the  cross-wire  ring  B B. 

Inverting  Eye-piece. — Sometimes,  especially  in 
English  instruments,  an  eye-piece  of  two  lenses  is  employed  ; 
but  this,  while  it  gives  more  light,  inverts  the  object  seen, 
and  so  has  been  discarded  by  American  engineers. 

Diagonal  Prism . — Where  it  is  desired  to  take 
greater  vertical  angles  than  is  possible  with  the  ordinary 
eye-piece,  the  little  cap  on  the  end  of  the  eye-piece  is  un- 
screwed and  replaced  by  another  containing  a small  prism 
(Fig.  13)  which  reflects  the  image  of  the  object  at  right 
angles,  and  brings  it  to  the  eye  of  an  observer  from  above ; 
when  used  on  the  sun,  a colored  glass  or  darkener  is  inter- 
posed between  the  eye  and  prism. 

How  Vision  is  Aided  by  the  Telescope . — The 
object-glass  receiving  the  rays  of  light  which  proceed  from 
all  the  points  of  a visible  object,  converges  them  to  a focus 
at  the  cross-wires,  and  there  forms  a minute,  inverted,  and 
very  bright  image,  which  may  be  seen  by  placing  a piece  of 
ground  glass  to  receive  it  at  that  point. 

The  eye-piece  acting  as  a compound  microscope,  magni- 
fies this  image,  restores  it  to  its  natural  position,  and  con- 
veys it  to  the  eye. 

The  visual  angle  which  the  image  there  subtends,  is  as 
many  times  greater  than  that  which  would  be  formed  with- 
out the  use  of  the  telescope,  as  the  number  which  expresses 
its  magnifying  power. 

Thus,  a telescope  which  magnifies  twenty  times,  increases 
the  visual  angle  just  as  much,  and  therefore  diminishes  the 
apparent  distance  of  the  object  twenty  times — or  in  other 
words,  it  will  show  an  object  two  hundred  feet  distant,  with 
the  same  distinctness  as  if  it  was  distant  only  ten  feet  from 
the  naked  eye. 


30 


THE  ENGINEERS’  TRANSIT. 


High  Poivers. — It  might  be  supposed  that  the  greater 
the  power  of  a telescope,  the  better  ; but  in  practice,  beyond 
a certain  point,  this  is  found  to  be  incorrect. 

In  the  first  plaoe,  as  only  a given  amount  of  light  can 
enter  the  object-glass,  the  more  the  object  is  magnified  the 
less  clear  and  bright  will  it  appear  ; and  again,  the  higher 
the  power  the  more  difficult  will  it  be  to  precisely  focus  the 
telescope  and  to  complete  its  adjustment. 

We  have  found  that  a power  of  from  twenty  to  twenty- 
four  diameters  in  the  telescopes  of  transits  gives  the  best 
results  and  is  amply  sufficient  for  all  ordinary  practice. 

The  Kellner  Eye-piece 9 the  main  feature  of  which 
is  the  use  of  a compound  amplifying  lens,  as  shown  in 
Fig.  2,  in  place  of  the  single  one  heretofore  employed,  has 
sensibly  increased  the  brilliancy  of  the  object  and  secured 
a better  field.  This  is  now  applied  to  all  our  transit  tele- 
scopes. 

The  eye-piece  is  brought  to  its  proper  focus  usually  by 
twisting  its  milled  end,  the  spiral  movement  within  carry- 
ing the  eye-tube  out  or  in  as  desired;  sometimes  a pinion, 

like  that  which  focuses  the 
object-glass,  is  employed  for 
the  same  purpose. 

The  Cross-  Wires , Fig. 
3,  are  two  fibres  of  spider- 
web or  very  fine  platinum 
wire,  cemented  into  the  cuts 
on  the  surface  of  a metal 
ring,  at  right  angles  to  each 
other,  so  as  to  divide  the 
open  space  in  the  centre 
into  quadrants. 


TIIE  ENGINEERS’  TRANSIT. 


31 


To  remove  the  Cross-wire  ring. — Take  out  the 
eye-piece  tube,  together  with  the  little  ring  by  which  it  is 
centered,  and  having  removed  two  opposite  cross-wire 
screws,  with  the  others  turn  the  ring  until  one  of  the  screw 
holes  is  brought  into  view  from  the  open  end  of  the  tele- 
scope tube,  in  this  thrust  a pointed  splinter  of  wood  or  a 
small  wire,  so  as  to  hold  the  ring  when  the  remaining 
screws  are  withdrawn;  the  ring  is  then  taken  out. 

♦ 

It  may  be  replaced  by  returning  it  to  its  position  in  the 
tube,  and  either  pair  of  screws  being  inserted,  the  splinter 
or  wire  is  removed,  and  the  ring  is  tu.rned  until  the  other 
screws  can  be  replaced. 

Care  must  also  be  taken  that  the  same  side  of  the  ring  is 
turned  to  the  eye-piece  as  before  it  was  removed. 

When  this  has  been  done,  the  eye-tube  is  inserted,  and  its 
centering  ring  brought  into  such  a position  that  the  screws 
in  it  can  be  replaced,  and  then  by  screwing  on  the  end  of 
the  telescope,  the  little  cover  into  which  the  eye-tube  is 
fixed,  the  operation  will  be  completed. 

The  advantaffe  of  Platinum  over  Spider-web 

for  the  cross-wires  of  telescopes  has  long  been  conceded, 
but  the  difficulty  of  procuring  it  of  sufficient  fineness  has 
prevented  its  general  adoption.  We  are  now  successfully 
drawing  platinum  wires  of  a fineness  of  from  one  eight- 
thousandth  to  one  twelve-thousandth  of  an  inch,  and  are 
using  them  in  the  telescopes  of  all  our  instruments,  unless 
spider-lines  are  specially  ordered. 

These  wires  are  perfectly  opaque,  and  of  course  entirely 
unaffected  by  moisture,  and  we  believe  they  will  be  univer- 
sally preferred  to  the  spider-web  heretofore  used. 


32 


THE  ENGINEERS’  TRANSIT. 


Optical  Axis. — The  intersection  of  the  wires  forms  a 
very  minute  point,  which,  when  they  are  adjusted,  deter- 
mines the  optical  axis  of  the  telescope,  and  enables  the 
surveyor  to  fix  it  upon  an  object  with  the  greatest  pre- 
cision. 

The  imaginary  line  passing  through  the  optical  axis  of 
the  telescope,  is  termed  the  “ line  of  collimation,”  and  the 
operation  of  bringing  the  intersection  of  the  wires  into  the 
optical  axis,  is  called  the  “adjustment  of  the  line  of  colli- 
mation.” This  will  be  hereafter  described. 

The  openings  in  the  telescope  tube  are  made  considerably 
larger  than  the  screws,  so  that,  when  these  are  loosened,  the 
whole  ring  can  be  turned  around  for  a short  distance  in 
either  direction. 

The  object  of  this  will  be  seen  more  plainly,  when  we 
describe  the  means  by  which  the  wire  is  made  truly  ver- 
tical. 

The  sectional  view  of  the  telescope  (Fig.  2)  also  shows 
two  movable  rings,  one  placed  at  A A,  the  other  at  C C, 
which  are  respectively  used,  to  effect  the  centering  of 
the  eye-piece,  and  the  adjustment  of  the  object-glass 
slide. 

The  centering  of  the  eye-tube  is  performed  after  the 
wires  have  been  adjusted,  and  is  effected  by  moving  the 
ring,  by  means  of  the  screws  shown  on  the  outside  of  the 
tube,  until  the  intersection  of  the  wires  is  brought  into  the 
centre  of  the  field  of  view. 


THE  ENGINEERS’  TRANSIT. 


33 


The  adjustment  of  the  object-slide,  which  will  be  here- 
after described,  secures  the  movement  of  the  object-glass  in 
a straight  line,  and  thus  keeps  the  line  of  collimation  in 
adjustment  through  the  whole  range  of  the  slide,  prevent- 
ing at  the  same  time  what  is  termed  the  “traveling”  of 
the  wires. 

This  adjustment,  which  is  peculiar  to  our  telescopes,  is 
always  made  in  the  process  of  construction,  and  needing  no 
further  attention  at  the  hands  of  the  engineer,  is  concealed 
within  the  ring  near  the  ball  of  the  telescope  axis. 


The  Stadia , or  Micrometer , is  a compound  cross- 
wire ring  or  diaphragm,  shown  in  Figures  4 and  5,  having 
three  horizontal  wires,  of  which  the  middle  one  is  cemented 
to  the  ring  as  usual,  while  the  others,  bb  and  cc,  are  fastened 
to  small  slides,  held  apart  by  a slender  brass  spring  hoop, 
and  actuated  by  independent  screws,  dd , by  which  the  dis- 
tance between  the  two  movable  wires  can  be  adjusted  to 
include  a given  space,  as  one  foot  on  a rod  one  hundred 
feet  distant.  These  wires  will  in  the  same  manner  include 
two  feet  on  a rod  two  hundred  feet  distant,  or  half  a foot 
at  a distance  of  fifty  feet,  and  so  on  in  the  same  proportion, 


34 


THE  ENGINEERS’  TRANSIT. 


thus  furnishing  a means  of  measuring  distances,  especially 
over  broken  ground,  much  more  easily  and  even  more 
accurately  than  with  a tape  or  chain. 

Attachments  to  Telescope . — In  Fig.  1,  the  telescope 
is  represented  as  plain,  or  without  any  attachments  such  as 
vertical  circle,  level,  etc.,  but  many  if  not  most  engineers 
prefer  to  have  two  or  more  of  these  accessories.  They  are 
represented  and  described  in  the  following  articles,  and  can 
be  attached  to  this  or  any  other  transit  as  desired. 

The  Standards  of  the  Transit  are  firmly  attached 
by  their  expanded  bases  to  the  upper  plate,  one  of  them 
having  near  the  top,  as  shown  in  the  cut,  a little  movable 
box,  actuated  by  a screw  underneath,  by  which  the  tele- 
scope axis  is  made  truly  horizontal,  as  will  be  hereafter 
described. 


The  circular  plates,  with  their  accompanying  sockets, 
are  shown  in  section  in  Fig.  6;  the  upper  plate,  A A, 


THE  ENGINEERS’  TRANSIT. 


55 


carrying  the  compass  circle,  etc.,  is  screwed  fast  to  the 
flange  of  the  interior  spindle;  the  lower  plate  or  divided 
limb,  B B,  is  fastened  to  the  exterior  socket  C,  which  again 
is  fitted  to  and  turns  in  the  hollow  socket  of  the  leveling 
head. 

The  compass  box,  containing  the  needle,  etc.,  is  covered 
by  a glass  to  exclude  the  moisture  and  air;  the  circle  is 
silvered,  and  is  divided  on  its  upper  surface  or  rim  into 
degrees  and  half-degrees,  the  degree  marks  being  also  cut 
down  on  its  inner  edge,  and  figured  from  0 to  90  on  each 
side  of  the  centre  or  line  of  zero. 

The  Magnetic  Needle  is  four  to  five  inches  long  in 
the  different  sizes  of  transits,  its  brass  cap  having  inserted 
in  it  a little  socket  or  centre  of  hardened  steel,  perfectly 
polished,  and  this  resting  upon  the  hardened  and  polished 
point  of  the  centre-pin,  allows  the  needle  to  play  freely  in 
a horizontal  direction,  and  thus  take  its  direction  in  the 
magnetic  meridian.  The  needle  has  its  north  end  desig- 
nated by  a scollop  or  other  mark,  and  on  its  south  end 
a small  coil  of  fine  brass  wire,  easily  moved,  so  as  to  bring 
both  ends  of  the  needle  to  the  same  level.  The  needle  is 
lifted  from  the  pin  by  a concealed  spring  underneath  the 
upper  plate,  actuated  by  a screw  shown  above,  thus  raising 
the  button  so  as  to  check  the  vibrations  of  the  needle,  or 
bring  it  up  against  the  glass  when  not  in  use,  to  avoid  the 
unnecessary  wear  of  the  pivot. 

The  forms  of  the  needle  are  almost  infinitely  varied, 
according  to  the  taste  or  fancy  of  the  maker  or  surveyor, 
but  may  be  resolved  into  two  general  classes,  one  having 
the  greatest  breadth  in  a horizontal,  the  other  in  a vertical 
direction. 

We  have  usually  made  our  needles  about  one-twentieth  of 
an  inch  broad  and  one-third  as  thick,  parallel  from  end  to 
end,  and  find  that  they  are  generally  acceptable,  but  when- 


36 


THE  ENGINEERS’  TRANSIT. 


ever  desired,  supply  other  forms  and  without  additional 
charge. 

The  test  of  the  delicacy  of  a magnetic  needle  is  the  num- 
ber of  horizontal  vibrations  which  it  will  make  in  a certain 
arc,  before  coming  to  rest — besides  this  most  surveyors 
prefer  also  to  see  a sort  of  quivering  motion  in  a vertical 
direction. 

*/This  quality,  which  is  manifested  more  in  a horizontal 
than  in  a vertical  needle,  and  depends  upon  the  near  coin- 
cidence of  the  point  of  suspension  with  the  centre  of  gravity 
of  the  needle,  serves  to  show  merely  that  the  cap  below  is 
unobstructed. 

The  Clamp  and  Tangent  Movement , shown  in 
Fig.  1 on  the  upper  plate,  serves  to  fasten  the  two  plates  to- 
gether, so  that  by  the  tangent  screw  they  can  be  slowly  moved 
around  each  other  in  either  direction,  or  loosened  at  will 
and  moved  by  the  hand,  thus  enabling  one  to  direct  the 
telescope  rapidly  and  accurately  to  the  point  of  sight. 

The  opening  for  the  clamp  in  the  upper  plate  is  covered 
by  a plate  or  washer,  as  shown,  to  exclude  the  dust  and 
moisture — the  clamping  piece  into  which  the  clamp-screw 
enters  is  shown  at  D,  Fig.  6. 

The  two  Levels  are  shown  placed  at  right  angles  to 
each  other  so  as  to  level  the  plate  in  all  directions,  and 
adjusted  by  turning  the  capstan  head-screws  at  their  ends, 
by  a small  steel  adjusting  pin.  The  glass  vials  used  in  the 
levels  of  this  and  all  our  Transits  are  ground  on  their  upper 
interior  surface,  so  as  to  make  the  bubble  move  evenly  and 
with  great  sensitiveness. 

The  Lower  Plate  or  Limb  B B , Fig.  6,  is  divided 
on  its  upper  surface — usually  into  degrees  and  half-degrees — 
and  figured  in  two  rows,  viz.,  from  0 to  360,  and  from  0 to 
90  each  way  ; sometimes  but  a single  series  is  used,  and 
then  the  figures  run  from  0 to  360  or  from  0 to  180  on 


THE  ENGINEERS’  TRANSIT. 


3 


each  side.  The  figuring,  which  is  the  same  upon  this  as 
the  limbs  of  all  our  Transits,  is  varied  according  to  the  wish 
of  the  person  ordering  the  instrument,  the  double  series 
being  always  used  unless  otherwise  desired. 

The  two  verniers  VV  are  attached  to  the  upper  plate 
diametrically  opposite  to  each  other,  and  serve  to  read  the 
limb  around  which  they  revolve. 

The  Verniers  are  double,  having  on  each  side  of  the 
zero  mark  thirty  equal  divisions  corresponding  precisely 
with  twenty-nine  half  degrees  of  the  limb ; they  thus  read 
to  single  minutes,  and  the  number  passed  over  is  counted 
in  the  same  direction  in  which  the  vernier  is  moved. 

The  use  of  two  opposite  verniers  in  this  and  other  instru- 
ments gives  the  means  of  “ cross  questioning”  the  gradua- 
tions, the  perfection  with  which  they  are  centered  and  the 
dependence  which  can  be  placed  upon  the  accuracy  of  the 
angles  indicated. 

Sometimes  a finer  reading  than  minutes  is  desired,  and 
then  the  divisions  of  the  limb  and  vernier  are  both  made 
smaller,  so  as  to  give  readings  to  30,  20,  or  even  10  seconds 
of  arc,  if  required.  The  vernier  openings  are  covered  with 
glass,  carefully  cemented  to  exclude  the  moisture  and 
dust. 

Keflectors  of  silver  or  celluloid,  as  in  the  Mountain 
Transit,  are  often  used  to  throw  more  light  upon  the 
divisions,  and  more  rarely,  shades  of  ground  glass  are 
employed  to  give  a clear  but  more  subdued  light. 

The  Graduations  are  made  commonly  on  the  brass 
surface  of  the  limb,  afterwards  filled  with  black  wax,  and 
then  finished  and  silvered.  Many  instruments,  however, 
have  a solid  silver  plate  put  over  the  brass,  and  the  gradua- 
tions made  on  the  silver  itself. 

The  last  is  more  costly  but  ensures  a finer  graduation, 
with  less  liability  to  tarnish  or  change  color. 


38 


THE  ENGINEERS’  TRANSIT. 


The  Sockets  of  the  Transit,  as  shown  in  Fig.  6,  are 
compound ; the  interior  spindle  attached  to  the  vernier 
plate,  turning  in  the  exterior  socket  C when  an  angle  is 
taken  on  the  limb,  but  when  the  plates  are  clamped  to- 
gether, the  exterior  socket  itself,  and  with  it  the  whole 
instrument,  revolves  in  the  socket  of  the  leveling  head. 

The  sockets  are  made  with  the  greatest  care,  the  surfaces 
being  truly  concentric  with  each  other,  and  the  bell  metal 
or  composition  of  which  they  are  composed,  of  different 
degrees  of  hardness,  so  as  to  cause  them  to  move  upon  each 
other  easily  and  with  the  least  possible  wear. 

The  leveling  head,  also  shown  in  Fig.  6,  consists  of  two 
plates  connected  together  by  a socket,  having  at  its  end  a 
hemispherical  nut,  fitting  into  a corresponding  cavity  in 
the  lower  plate. 

The  plates  are  inclined  to  each  other  or  made  parallel  at 
will  by  four  leveling  screws,  of  which  only  two  are  shown 
in  the  section. 

The  screws  are  of  bronze  or  hard  composition  metal  and 
fitted  to  long  nuts  of  brass,  screwed  into  the  upper  parallel 
plate;  and,  as  will  be  noticed,  have  threads  only  on  the 
upper  ends,  the  lower  part  of  their  stems  turning  closely 
in  the  lower  unthreaded  part  of  the  nuts. 

By  this  arrangement  dust  is  excluded  from  the  lower  end 
of  the  screws,  while  the  brass  cover  above  equally  protects 
the  other  end. 

The  screws  rest  in  little  cups  or  sockets,  which  are 
secured  to  their  ends  and  in  which  they  turn  without  mar- 
ring the  surface  of  the  lower  plate,  the  cups  also  permitting 
the  screws  to  be  shifted  from  side  to  side,  or  turned  around 
in  either  direction  on  the  lowrer  plate. 

The  clamp  and  tangent  movement  of  the  leveling  head, 
partially  shown  in  Fig.  1,  serves  to  turn  the  whole  instru- 
ment upon  its  sockets,  so  as  to  fix  the  telescope  with  pre- 


THE  ENGINEERS’  TRANSIT. 


39 


cision  upon  any  given  point — and  when  unclamped  allow- 
ing it  to  be  directed  approximately  by  hand.  The  tangent 
screws,  as  will  be  seen,  press  on  opposite  sides  of  the  clamp- 
piece,  and  thus  ensure  a very  fine  and  solid  movement  of 
the  instrument. 

The  Lower  Leveling -plate  is  made  in  two  pieces— 
the  upper  one,  which  is  screwed  fast  to  the  top  of  the  tri- 
pod, having  a large  opening  in  its  centre,  in  which  the 
smaller  lower  one  is  shifted  from  side  to  side,  or  turned 
completely  around. 

By  this  simple  arrangement,  termed  a “shifting  centre,” 
the  instrument  is  easily  moved  over  the  upper  plate,  and 
the  plummet  which  hangs  from  the  centre  P,  Fig.  6, 
set  precisely  over  a point,  without  moving  the  tripod. 

The  Leveling  Head  of  the  Engineers*  Transit  is 
attached  to  the  sockets  by  a screw  and  washer  below;  it 
can  be  removed  for  cleaning,  oiling,  &c.,  but  should  be  in 
place  when  the  instrument  is  in  use,  or  packed  for  trans- 
portation. 

The  Tripod y the  top  of  which  is  shown  in  Fig.  1,  has 
three  mahogany  legs,  the  upper  ends  of  which  are  pressed 
firmly  on  each  side  of  a strong  tenon  on  the  solid  bronze 
head  by  a bolt  and  nut  on  opposite  sides  of  the  leg  ; the 
nut  can  also  be  screwed  up  at  will  by  a wrench  furnished 
for  the  purpose,  and  thus  kept  firm. 

The  lower  end  of  the  leg  has  a brass  shoe  with  iron 
point,  securely  fastened  and  riveted  to  the  wood. 

The  Extension  Tripod  described  and  figured  in  the 
article  “Mountain  Transit”  is  often  used  with  the  other 
larger  instruments,  and  is  then  made  heavier  and  stronger 
than  with  the  one  just  named. 

To  Adjust  the  Transit . — Every  instrument  should 
leave  the  hands  of  the  maker  in  complete  adjustment,  but 
all  are  so  liable  to  derangement  by  accident  or  careless  use, 


40 


THE  ENGINEERS’  TRANSIT. 


that  we  deem  it  necessary  to  describe  particularly  those 
which  are  most  likely  to  need  attention. 

The  principal  adjustments  of  the  Transit  are — 

(1)  The  Levels . 

(2)  The  Line  of  Collimation. 

(3)  The  Standards . 

To  Adjust  the  Levels . — Set  up  the  instrument  upon 
its  tripod  as  nearly  level  as  may  be,  and  having  unclamped 
the  plates,  bring  the  two  levels  above  and  on  a line  with  the 
twT)  pairs  of  leveling  screws ; then  with  the  thumb  and  first 
finger  of  each  hand  clasp  the  heads  of  two,  opposite ; and, 
turning  both  thumbs  in  or  out,  as  may  be  needed,  bring  the 
bubble  of  the  level  directly  over  the  screws,  exactly  to  the 
centre  of  the  opening.  Without  moving  the  instrument 
proceed  in  the  same  manner  to  bring  the  other  bubble  to 
its  centre ; after  doing  this,  the  level  first  corrected  may  be 
thrown  a little  out  ; bring  it  in  again  ; and  when  both  are 
in  place,  turn  the  instrument  half-way  around ; if  the  bub- 
bles both  come  to  the  centre,  they  would  need  no  correc- 
tion, but  if  not,  with  the  adjusting  pin  turn  the  small 
screws  at  the  end  of  the  levels  until  the  bubbles  are  moved 
over  half  the  error  ; then  bring  the  bubbles  again  into  the 
centre  by  the  leveling  screws,  and  repeat  the  operation  un- 
til the  bubbles  will  remain  in  the  centre  during  a complete 
revolution  of  the  instrument,  and  the  adjustment  will  be 
complete.  It  should  be  remarked  that  in  this,  as  in  most 
of  our  Transits,  the  level  on  the  standards  has  a move- 
ment only  at  one  end,  the  adjustment  being  made  by  abut- 
ting screws,  which  are  loosened  and  tightened  in  turn,  in 
moving  the  level. 

To  Adjust  the  Line  of  Collimation —To  make 
this  adjustment — which  is,  in  other  words,  to  bring  the  inter- 
section of  the  wires  into  the  optical  axis  of  the  telescope,  so 
that  the  instrument,  when  placed  in  the  middle  of  a 


THE  ENGINEERS’  TRANSIT. 


41 


straight  line,  will,  by  the  revolution  of  the  telescope,  cut 
its  extremities — proceed  as  follows: 

Set  the  instrument  firmly  on  the  ground  and  level  it 
carefully;  and  then  having  brought  the  wires  into  the 
focus  of  the  eye-piece,  adjust  the  object-glass  on  some  well- 
defined  point,  as  the  edge  of  a chimney  or  other  object,  at 
a distance  of  from  two  hundred  to  five  hundred  feet;  deter- 
mine if  the  vertical  wire  is  plumb,  by  clamping  the  instrument 
firmly  and  applying  the  wire  to  the  vertical  edge  of  a build- 
ing, or  observing  if  it  will  move  parallel  to  a point  taken  a 
little  to  one  side ; should  any  deviation  be  manifested, 
loosen  the  cross-wire  screws,  and  by  the  pressure  of  the 
hand  on  the  head  outside  the  tube,  move  the  ring  around 
until  the  error  is  corrected. 

The  wires  being  thus  made  respectively  horizontal  and 
vertical,  fix  their  point  of  intersection  on  the  object 
selected  ; clamp  the  instrument  to  the  spindle,  and  having 
revolved  the  telescope,  find  or  place  some  good  object  in 
the  opposite  direction,  and  at  about  the  same  distance  from 
the  instrument  as  the  first  object  assumed. 

Great  care  should  always  be  taken  in  turning  the  teles- 
cope, that  the  position  of  the  instrument  upon  the  spindle 
is  not  in  the  slightest  degree  disturbed. 

Now,  having  found  or  placed  an  object  which  the  ver- 
tical wire  bisects,  unclamp  the  instrument,  turn  it  half  way 
around,  and  direct  the  telescope  to  the  first  object  selected  ; 
having  bisected  this  with  the  wires,  again  clamp  the  in- 
strument, revolve  the  telescope,  and  note  if  the  vertical 
wire  bisects  the  second  object  observed. 

Should  this  happen,  it  will  indicate  that  the  wires  are  in 
adjustment,  and  the  points  bisected  are  with  that  of  the 
centre  of  the  instrument,  in  the  same  straight  line. 

If  not,  however,  the  space  which  separates  the  wires  from 
the  second  point  observed,  will  be  double  the  deviation  of 


42 


THE  EKGINEERS  transit. 


that  point  from  a true  straight  line,  which  may  be  con- 
ceived as  drawn  through  the  first  point  and  the  centre  of 
the  instrument,  since  the  error  is  the  result  of  two  observa- 
tions, made  with  the  wires  when  they  are  out  of  the  optical 
axis  of  the  telescope. 


For,  as  in  the  diagram,  let  A represent  the  centre  of  the 
instrument,  and  B C the  imaginary  straight  line,  upon  the 
extremities  of  which  the  line  of  collimation  is  to  be  ad- 
justed. 

B represents  the  object  first  selected,  and  D the  point 
which  the  wires  bisected,  when  the  telescope  was  made  to 
revolve. 

When  the  instrument  is  turned  half  around,  and  the 
telescope  again  directed  to  B,  and  once  more  revolved,  the 
wires  will  bisect  an  object,  E,  situated  as  far  to  one  side  of 
the  true  line  as  the  point  D is  on  the  other  side. 

The  space,  D E,  is  therefore  the  sum  of  two  deviations  of 
the  wires  from  a true  straight  line,  and  the  error  is  made 
very  apparent. 

In  order  to  correct  it,  use  the  two  capstan  head  screws  on 
the  sides  of  the  telescope,  these  being  the  ones  which  affect 
the  position  of  the  vertical  wire. 

Kemember  that  the  eye-piece  inverts  the  position  of  the 
wires,  and  therefore  that  in  loosening  one  of  the  screws 
and  tightening  the  other  on  the  opposite  side,  the  operator 
must  proceed  as  if  to  increase  the  error  observed.  Having 
in  this  manner  moved  back  the  vertical  wire  until,  by  esti- 
mation, one-qnarter  of  the  space,  D E,  has  been  passed 


D 


B 


Fig.  7. 


THE  ENGINEERS'  TRANSIT. 


43 


over,  return  the  instrument  to  the  point  B,  revolve  the 
telescope,  and  if  the  correction  has  been  carefully  made, 
the  wires  will  now  bisect  a point,  C,  situated  midway  be- 
tween D and  E,  and  in  the  prolongation  of  the  imaginary 
line,  passing  through  the  point  B and  the  centre  of  the  in- 
strument. 

To  ascertain  if  such  is  the  case,  turn  the  instrument  half 
around,  fix  the  telescope  upon  B,  clamp  to  the  spindle, 
and  again  revolve  the  telescope  towards  C.  If  the  wires 
again  bisect  it,  it  will  prove  that  they  are  in  adjustment, 
and  that  the  points,  B,  A.  C,  all  lie  in  the  same  straight 
line. 

Should  the  vertical  wire  strike  to  one  side  of  C,  the  error 
must  be  corrected  precisely  as  above  described,  until  it  is 
entirely  removed. 

Another  method  of  adjusting  the  line  of  collimation 
often  employed  in  situations  where  no  good  points  in  oppo- 
site directions  can  be  selected  upon  which  to  reverse  the 
wires,  may  here  be  described. 

The  operator  sets  up  the  instrument  in  some  position 
which  commands  a long  sight  in  the  same  direction,  and 
having  leveled  his  instrument,  clamps  to  the  spindle,  and 
with  the  telescope  locates  three  points  which  we  will  term 
A,  B and  C,  which  are  distant  from  the  instrument  about  one 
hundred,  two  hundred,  and  three  hundred  feet  respectively. 

These  points,  which  are  usually  determined  by  driving  a 
nail  into  a wooden  stake  set  firmly  into  the  ground,  will  all 
be  in  the  same  straight  line,  however  much  the  wires  are 
out  of  adjustment,  since  the  position  of  the  instrument 
remains  unchanged  during  the  whole  operation. 

Having  fixed  these  points  he  now  moves  the  instrument 
to  B,  and  sets  its  centre  directly  over  the  nail-head,  by  let- 
ting down  upon  it  the  point  of  a plumb-bob  suspended  from 
the  tripod. 


44 


THE  ENGINEERS’  TRANSIT. 


Then  having  leveled  the  instrument,  he  directs  the  wires 
to  A,  clamps  to  the  spindle  and  revolves  the  telescope 
towards  C.  Should  the  wires  strike  the  nail  at  that  point, 
it  would  show  that  they  were  in  adjustment. 

Should  any  deviation  be  observed,  the  operator  must  cor- 
rect it  by  moving  the  wire  with  the  screws  until,  by  esti- 
mation, half  the  error  is  removed. 

Then  bringing  the  telescope  again  upon  either  A or  C, 
and  revolving  it,  he  will  find  that  the  wires  will  strike  the 
point  in  the  opposite  direction  if  the  proper  correction  has 
been  applied. 

If  not,  repeat  the  operation  until  the  telescope  will  ex- 
actly cut  the  two  opposite  points,  when  the  intersection  of 
the  wires  will  be  in  the  optical  axis,  and  the  line  of  collima- 
tion  in  adjustment. 

In  our  description  of  the  previous  operation,  we  have 
spoken  more  particularly  of  the  vertical  wire,  because  in  a 
revolving  telescope  this  occupies  the  most  important  place, 
the  horizontal  one  being  employed  mainly  to  define  the 
centre  of  the  vertical  wire,  so  that  it  may  be  moved  either 
up  or  down  without  materially  disturbing  the  line  of  colli- 
mation. 

The  wires  being  adjusted,  their  intersection  may  now  be 
brought  into  the  centre  of  the  field  of  view  by  moving  the 
screws  A A,  shown  in  the  sectional  view  of  the  telescope, 
Fig  2,  which  are  slackened  and  tightened  in  pairs,  the 
movement  being  now  direct,  until  the  wires  are  seen  in 
their  proper  position. 

It  is  here  proper  to  observe,  that  the  position  of  the  line 
of  collimation  depends  upon  that  of  the  object-glass,  solely, 
so  that  the  eye-piece  may,  as  in  the  case  just  described,  be 
moved  in  any  direction,  or  even  entirely  removed  and  a new 
one  substituted,  without  at  all  deranging  the  adjustment  of 
the  wires. 


THE  ENGINEERS’  TRANSIT. 


45 


To  Adjust  the  Standards. — In  order  that  the  wires 
may  trace  a vertical  line  as  the  telescope  is  moved  up  or 
down,  it  is  necessary  that  both  the  standards  of  the  teles- 
cope should  be  of  precisely  the  same  height. 

To  ascertain  this  and  make  the  correction  if  needed,  pro- 
ceed as  follows : 

Having  the  line  of  collimation  previously  adjusted,  set 
up  the  instrument  in  a position  where  points  of  observa- 
tion, such  as  the  point  and  base  of  a lofty  spire,  can  be 
selected,  giving  a long  range  in  a vertical  direction. 

Level  the  instrument,  fix  the  wires  on  the  top  of  the  ob- 
ject and  clamp  to  the  spindle;  then  bring  the  telescope 
down,  until  the  wires  bisect  some  good  point,  either  found 
or  marked  at  the  base ; turn  the  instrument  half  around, 
fix  the  wires  on  the  lower  point,  clamp  to  the  spindle,  and 
raise  the  telescope  to  the  highest  object. 

If  the  wires  bisect  it,  the  vertical  adjustment  is  effected  ; 
if  they  are  thrown  to  either  side  this  would  prove  that  the 
standard  opposite  that  side  was  the  highest,  the  apparent 
error  being  double  that  actually  due  to  this  cause. 

To  correct  it,  we  make  one  of  the  bearings  of  the  axis 
movable,  so  that  by  turning  a screw  underneath  this  sliding 
piece,  as  well  as  the  screws  which  hold  on  the  cap  of  the 
standard,  the  adjustment  is  made  with  the  utmost  pre- 
cision. 

This  arrangement,  which  is  common  to  all  our  telescope 
instruments,  is  very  substantial  and  easily  managed. 


Other  Adjustments  of  the  Transit . 

Besides  the  three  adjustments  already  described — which 
are  all  that  the  Surveyor  will  ordinarily  have  to  make — there 
are  those  of  the  needle  and  the  object-glass  slide,  which 
may  sometimes  be  required. 


46 


THE  EHGINEERS  TRAHSIT. 


The  first  is  best  given  with  the  description  of  the  Com- 
pass— the  last  will  now  be  described* 

To  Adjust  the  Object-slide . — Having  set  up  and 
leveled  the  instrument,  the  line  of  collimation  being  also 
adjusted  for  objects  from  three  hundred  to  five  hundred  feet 
distant,  clamp  the  plates  securely,  and  fix  the  vertical  cross- 
wire  upon  an  object  as  distant  as  may  be  distinctly  seen ; then, 
without  disturbing  the  instrument,  throw  out  the  object- 
glass,  so  as  to  bring  the  vertical  wire  upon  an  object  as 
near  as  the  range  of  the  telescope  will  allow.  Having  this 
clearly  in  mind,  unclamp  the  limb,  turn  the  instrument 
half-way  around,  reverse  the  eye-end  of  the  telescope,  clamp 
the  limb,  and  with  the  tangent-screw  bring  the  vertical 
wire  again  upon  the  near  object  ; then  draw  in  the  object- 
glass  slide  until  the  distant  object  first  sighted  upon  is 
brought  into  distinct  vision.  If  the  vertical  wire  strikes 
the  same  line  as  at  first,  the  slide  is  correct  for  both  near 
and  remote  objects  ; and,  being  itself  straight,  for  all  dis- 
tances. 

But  if  there  be  an  error,  proceed  as  follows  : first,  with 
the  thumb  and  forefinger  twist  off  the  thin  brass  tube  that 
covers  the  screws  C C shown  in  Fig.  2.  Next,  with  the 
screw-driver,  turn  the  two  screws  C C on  the  opposite  sides 
of  the  telescope,  loosening  one  and  tightening  the  other, 
so  as  apparently  to  increase  the  error,  making,  by  estima- 
tion, one-half  the  correction  required. 

Then  go  over  the  usual  adjustment  of  the  line  of  col- 
limation, and  having  it  completed,  repeat  the  operation 
above  described  ; first  sighting  upon  the  distant  object, 
then  finding  a near  one  in  line,  and  then  reversing, 
making  correction,  &c.,  until  the  adjustment  is  com- 
plete. 

This  adjustment  is  always  made  by  us  before  the  instru- 
ment is  shipped,  is  peculiar  to  our  Transits,  and,  in  our 


THE  ENGINEERS’  TRANSIT. 


47 


experience,  furnishes  the  only  way  in  which  the  line  of 
collimation  can  be  made  correct  for  all  distances. 

To  Use  the  Transit.— The  instrument  should  be  set 
up  firmly,  the  tripod  legs  being  pressed  into  the  ground,  so  as 
to  bring  the  plates  as  nearly  level  as  convenient ; the  plates 
should  then  be  carefully  leveled  and  properly  clamped,  the 
zeros  of  the  verniers  and  limb  brought  into  line  by  the 
upper  tangent-screw,  and  the  telescope  directed  to  the 
object  by  the  tangent-screws  of  leveling  head. 

The  angles  taken  are  then  read  off  upon  the  limb,  with- 
out subtracting  from  those  given  by  the  verniers,  in  any 
other  position. 

Before  an  observation  is  made  with  the  telescope,  the 
eye-piece  should  be  moved  in  or  out,  until  the  wires  appear 
distinct  to  the  eye  of  the  operator  ; the  object-glass  is  then 
adjusted  by  turning  the  pinion-head  until  the  object  is  seen 
clear  and  well-defined,  and  the  wires  appear  as  if  fastened 
to  its  surface. 

The  intersection  of  the  wires,  being  the  means  by  which 
the  optica]  axis  of  the  telescope  is  defined,  should  be 
brought  precisely  upon  the  centre  of  the  object  to  which 
the  instrument  is  directed. 

The  needle  is  used,  as  in  the  compass,  to  give  the  bearing 
of  lines,  and  as  a rough  check  upon  the  angles  obtained  by 
the  verniers  and  limb  ; but  its  employment  is  only  sub- 
sidiary to  the  general  purposes  of  the  Transit. 

The  Attach  meats  of  the  Transit. — The  engraving 
of  the  Surveyors’  Transit  hereafter  described,  represents  the 
attachments  often  applied  to  the  Engineers’  Transit,  viz  : 
vertical  circle,  level  on  telescope,  and  clamp  and  tangent  to 
telescope  axis.  They  are  of  use  where  approximate  leveling 
and  vertical  angles  are  to  be  taken  in  connection  with  the 
ordinary  use  of  the  Transit,  and  with  their  adjustments,&c., 
will  be  described  in  the  account  of  the  Surveyors’  Transit. 


48 


THE  ENGINEERS’  TRANSIT. 


ENGINEERS’  TRANSIT. 


Fig.  8. 


5-inch  Engineers’  Transit  with  Solar  Attachment. 
Price  as  shown,  including  tripod,  $250.00. 


THE  ENGINEERS*  TRANSIT. 


49 


ENGINEERS’  TRANSIT  WITH  SOLAR  ATTACH- 
MENT. 

The  engraving  represents  our  Engineers’  Transit  with 
5-inch  needle  and  attachments  of  vertical  arc,  6 inches  in 
diameter,  divided  on  silver,  reading  to  thirty  seconds — 
level  on  telescope — clamp  and  tangent  to  axis  and  solar 
apparatus — with  declination  arc  reading  to  thirty  seconds. 

The  compass  circle  is  also  made  movable,  with  pinion 
and  clamp,  for  setting  off  the  variation  of  the  needle. 

For  price  of  the  instrument  thus  represented,  refer  to 
No.  5 in  Price  List. 


50 


THE  ENGINEERS’  TRANSIT. 


The  Theodolite  Axis. 

In  place  of  the  ordinary  axis  of  the  telescope  represented 
in  Fig.  1,  we  sometimes  make  one  resembling  the  Y axis  of 
the  English  Theodolite. 

This  modification  is  desirable,  in  cases  where  this  instru- 
ment is  intended  to  subserve  the  purposes  of  both  level  and 
transit. 

In  such  an  arangement,  the  telescope  is  confined  in  the 
axis  with  clips,  by  loosening  which,  it  may  be  revolved  in 
the  wyes,  or  taken  out  and  reversed  end  for  end,  precisely 
like  that  of  the  Y leveling  instrument. 

The  standards  also  allow  its  transit,  or  complete  revolu- 
tion in  a vertical  direction. 

In  such  an  instrument,  the  adjustment  of  the  wires,  and 
level  of  the  telescope,  is  effected  in  the  same  manner  as 
those  of  the  leveling  instrument,  the  tangent  movement  of 
the  axis  serving,  instead  of  the  leveling  screws,  to  bring  the 
bubble  and  wires  into  position. 

When  desirable,  a vertical  wheel  may  be  placed  on  the 
axis  of  the  telescope  of  this  instrument,  and  thus  all  the 
properties  of  the  English  Theodolite  united  with  those  of 
the  American  Transit. 

PRICES. 

Engineers’  Transit,  two  verriers  to  limb,  5-incli  needle, 
plain  telescope,  theodolite  axis,  leveling  tripod $185  00 

Do  do  do.  with  vertical  circle,  level  on  tele- 
scope, clamp  and  tangent  to  axis 215  00 

Different  Sizes , with  Weights  of  Each. 

We  make  three  sizes  of  the  Engineers’  Transit,  having 
respectively  4,  4£,  and  5-inch  needles ; the  average  weight 
of  each  size,  with  plain  telescope,  excluding  the  tripod  head 
and  legs,  is  as  follows: 

4-inch  needle,  without  tripod,  13  pounds. 

4£  u « 14 

5 “ “ 16  “ 


LIGHT  MOUNTAIN  TRANSIT. 


51 


LIGHT  MOUNTAIN  TEANSIT. 


Fig.  9. 


Price  as  shown,  including  extension  tripod,  $245.00. 

This  instrument  is  a modification  of  the  Engineers’ 
Transit,  made  for  Mountain  and  Mine  Surveys,  but  appli- 
cable as  well  to  all  the  other  work  of  the  Engineer.  It  is 
made  exceedingly  light  and  portable,  its  needle  being  4 


52 


LIGHT  MOUNTAIN  TRANSIT. 


inches  long;  and  its  telescope  8 inches  long,  having  a 
power  of  20  diameters. 

Its  sockets  are  like  those  shown  in  Fig.  6,  and,  with  the 
leveling  head,  remain  attached  to  the  instrument;  and  its 
compass  circle  is  movable  about  its  centre,  like  that  of  the 
Eailroad  Compass,  hereafter  shown,  so  as  to  lay  off  the 
variation  of  the  needle  as  described  in  the  account  of  that 
instrument. 

In  this  instrument  the  limb  is  divided  on  solid  silver  to 
half  degrees,  with  verniers  reading  to  single  minutes ; 
sometimes  the  limb  is  divided  to  twenty  minutes  with 
verniers  reading  to  half  minutes. 

There  are  also  cylindrical  caps  above  the  leveling  screws 
to  exclude  the  dust,  &c.,  as  in  our  other  instruments. 

The  cut  shows  one  of  the  celluloid  reflectors,  which  are 
placed  over  the  two  opposite  verniers  of  the  limb,  and  are 
of  service  especially  in  the  surveys  of  mines,  to  throw  light 
upon  the  divisions  below. 

Attachments  of  the  Telescope . — Like  the  Engi- 
neers5 Transit  before  described,  this  instrument  is  sometimes 
used  with  a plain  telescope  ; but  oftener  with  one  or  more  of 
the  extras,  as  level,  clamp  and  tangent,  and  vertical  circle, 
as  shown  in  the  cut  of  the  Surveyors5  Transit. 

More  frequently,  however,  the  Mountain  Transit  is  fur- 
nished  as  shown,  with  vertical  arc,  level,  clamp  and  tangent, 
and  the  patent  solar  attachment,  the  last  of  which  we  shall 
now  proceed  to  describe,  referring  to  the  article  on  the 
Solar  Compass,  for  a more  detailed  account  of  the  principles 
involved  in  its  construction  and  use. 

The  Solar  Attachment  is  essentially  the  solar  appa- 
ratus of  Burt  placed  upon  the  cross-bar  of  the  ordinary 
transit,  the  polar  axis  being  directed  above  instead  of  below, 
as  in  the  solar  compass. 

A little  circular  disc  of  an  inch  and  a half  diameter, 
and  having  a short  round  pivot  projecting  above  its 


LIGHT  MOUNTAIN  TRANSIT. 


53 


upper  surface,  is  first  securely  screwed  to  the  telescope 
axis. 

Upon  this  pivot  rests  the  enlarged  base  of  the  polar  axis, 
which  is  also  firmly  connected  with  the  disc  by  four  capstan 
head  screws  passing  from  the  under  side  of  the  disc  into 
the  base  already  named. 

These  screws  serve  to  adjust  the  polar  axis,  as  will  be 
explained  hereafter. 

The  hour  circle  surrounding  the  base  of  the  polar  axis 
is  easily  movable  about  it,  and  can  be  fastened  at  any 
point  desired  by  two  flat-head  screws  above.  It  is  divided 
to  five  minutes  of  time  ; is  figured  from  I.  to  XII.,  and  is 
read  by  a small  index  fixed  to  the  declination  arc,  and  mov- 
ing with  it. 

A hollow  cone,  or  socket,  fitting  closely  to  the  polar  axis 
and  made  to  move  snugly  upon  it,  or  clamped  at  any  point 
desired  by  a milled-head  screw  on  top,  furnishes  by  its  two 
expanded  arms  below,  a firm  support  for  the  declination 
arc,  which  is  securely  fastened  to  it  by  two  large  screws, 
as  shown. 

The  declination  arc  is  of  about  five  inches  radius,  is 
divided  to  quarter  degrees,  and  reads  by  its  vernier  to  single 
minutes  of  arc,  the  divisions  of  both  vernier  and  limb  being 
in  the  same  plane. 

The  declination  arm  has  the  usual  lenses  and  silver  plates 
on  the  twTo  opposite  blocks,  made  precisely  like  those  of 
the  ordinary  solar  compass,  but  its  vernier  is  outside  the 
block,  and  more  easily  read. 

The  declination  arm  has  also  a clamp  and  tangent  move- 
ment, as  shown  in  the  cut.  The  arc  of  the  declination  limb 
is  turned  on  its  axis  and  one  or  the  other  solar  lens  used, 
as  the  sun  is  north  or  south  of  the  equator  ; the  cut  shows 
its  position  when  it  is  north. 

The  latitude  is  set  off  by  means  of  a large  vertical  limb 
3 


54 


LIGHT  MOUNTAIN  TRANSIT. 


having  a radius  of  two  and  a half  inches  ; the  arc  is  divided 
to  thirty  minutes,  is  figured  from  the  centre,  each  way,  in 
two  rows,  viz.  from  0 to  80°,  and  from  90°  to  10°,  the  first 
series  being  intended  for  reading  vertical  angles  ; the  last 
series  for  setting  off  the  latitude,  and  is  read  by  its  vernier 
to  single  minutes. 

When  desired,  an  arc  of  three  inches  radius  is  furnished, 
reading  by  its  vernier  to  half  minutes  of  a degree. 

It  has  also  a clamp-screw  inserted  near  its  centre,  by 
which  it  can  be  set  fast  to  the  telescope  axis  in  any  desired 
position. 

The  vernier  of  the  vertical  limb  is  made  movable  by  the 
tangent-screw  attached,  so  that  its  zero  and  that  of  the  limb 
are  readily  made  to  coincide  when,  in  adjusting  the  limb  to 
the  level  of  the  telescope,  the  arc  is  clamped  to  the  axis. 

The  usual  tangent  movement  to  the  telescope  axis  serves, 
of  course,  to  bring  the  vertical  limb  to  the  proper  elevation, 
as  hereafter  described. 

A level  on  the  under  side  of  the  telescope,  with  ground 
vial  and  scale,  is  indispensable  in  the  use  of  the  Solar 
attachment, 

The  divided  arcs,  verniers,  and  hour  circle  are  all  on 
silver  plate,  and  are  thus  easily  read  and  preserved  from 
tarnishing. 

Explanation  of  the  Solar  Apparatus . 

In  Fig.  10,  suggested  by  Prof.  L.  M.  Haupt,  author  of 
the  “Topographer,  his  Methods  and  Instruments,”  we  have 
a graphical  illustration  of  the  Solar  apparatus;  the  circles 
shown  being  illustrated  to  represent  in  miniature  those 
supposed  to  be  drawn  upon  the  concave  surface  of  the 
heavens. 

When  the  telescope  is  made  horizontal  by  its  spirit  level 
the  hour-circle  will  be  in  the  plane  of  the  horizon,  the  polar 


LIGHT  MOUNTAIN  TRANSIT. 


55 


THE  SOLAR  ATTACHMENT 


Fig.  10. 


56 


LIGHT  MOUNTAIN  TRANSIT. 


axis  will  point  to  the  zenith  and  the  zeros  of  the  vertical 
arc  and  its  vernier  coincide. 

In  this  position  of  the  instrument,  if  the  arm  of  the  dec- 
lination arc  be  placed  at  zero,  and  one  lens  directed  to  the 
sun,  his  image  will  be  seen  between  the  lines  on  the  silver 
plate  of  the  opposite  block,  as  shown  in  Fig.  26,  and  will 
indicate  his  position  in  the  heavens,  on  an  instrument  placed 
at  the  north  pole  of  the  earth  at  the  time  of  equinoxes,  or 
when  the  equator  is  in  the  plane  of  the  horizon. 

Now  if  we  incline  the  telescope  as  shown  in  the  cut,  the 
polar  axis  will  descend  from  the  direction  of  the  zenith. 
The  angle  through  which  it  moves,  being  laid  off  on  the 
vertical  arc,  and  shown  by  its  vernier  to  be  40°,  will  be  the 
co-latitude  of  the  place  where  the  instrument  is  supposed  to 
be  used,  the  latitude  itself  being  found  by  subtracting  40° 
from  90°,  making  it  just  50°. 

Now  if  the  declination  arm  remains  at  zero,  and  the  lens 
be  again  directed  to  the  sun,  his  image  will  appear  on  the 
opposite  plate  as  before,  the  instrument  being  used  at  the 
time  of  the  equinox  and  at  a latitude  of  50°. 

When,  however,  the  sun  passes  above  or  below  the  equa- 
tor, his  declination  or  angular  distance  from  it,  as  given  in 
the  Ephemeris,  can  be  allowed  for  and  set  off  upon  the  arc, 
and  his  image  brought  into  position  as  before. 

In  order  to  do  this,  however,  it  is  necessary  not  only  that 
the  latitude  and  declination  shall  be  correctly  set  off  upon 
their  respective  arcs,  but  also  that  the  instrument  should  be 
moved  in  azimuth  until  the  polar  axis  points  to  the  pole  of 
the  heavens,  or,  in  other  words,  is  placed  in  the  plane  of  the 
meridian,  and  thus  the  position  of  the  sun’s  image  will  in- 
dicate not  only  the  latitude  of  the  place,  the  declination  of 
the  sun  for  the  given  hour,  and  the  apparent  time,  but  also 
determine  the  meridian  or  true  north  and  south  line,  pass- 
ing through  the  place  where  the  observation  is  made. 


LIGHT  MOUNTAIN  TRANSIT. 


57 


The  Adjustments  of  the  Solar  Attachment. 

(1.)  The  Solar  lenses  and  lines  are  adjusted  pre- 
cisely like  those  of  the  ordinary  Solar,  the  declination  arm 
being  first  detached  by  removing  the  clamp  and  tangent 
screws,  and  the  conical  centre  with  its  two  small  screws,  by 
which  the  arm  is  attached  to  the  arc. 

The  adjuster,  which  is  a short  bar  furnished  with  every 
instrument,  is  then  substituted  for  the  declination  arm,  the 
conical  centre  screwed  into  its  place,  at  one  end,  and  the 
clamp-screw  into  the  other,  being  inserted  through  the  hole 
left  by  the  removal  of  the  tangent-screw,  thus  securing  the 
adjuster  firmly  to  the  arc. 

The  arm  is  then  turned  to  the  sun,  as  described  in  the 
article  on  the  Solar  Compass,  and  reversed  by  the  opposite 
faces  of  the  blocks  upon  the  adjuster,  until  the  image  will 
remain  in  the  centre  of  the  equatorial  lines.  This  adjust- 
ment is  very  rarely  needed  in  our  instruments,  the  lenses 
being  cemented  in  their  cells,  and  the  plates  securely  fast- 
ened. 

(2.)  The  vernier  of  the  declination  are  is 
adjusted  by  setting  the  vernier  at  zero,  and  then  raising  or 
lowering  the  telescope  by  the  tangent-screw  until  the  sun’s 
image  appears  exactly  between  the  equatorial  lines. 

Having  the  telescope  axis  clamped  firmly,  carefully  revolve 
the  arm  until  the  image  appears  on  the  other  plate. 

If  precisely  between  the  lines,  the  adjustment  is  complete; 
if  not,  move  the  declination  arm  by  its  tangent-screw,  until 
the  image  will  come  precisely  between  the  lines  on  the  two 
opposite  plates;  clamp  the  arm  and  remove  the  index  error 
by  loosening  two  screws  that  fasten  the  vernier;  place  the 
zeros  of  the  vernier  and  limb  in  exact  coincidence,  tighten 
the  screws,  and  the  adjustment  is  finished. 


58 


LIGHT  MOUNTAIN  'TRANSIT. 


(3.)  To  Adjust  the  Polar  Axis . — First  level  the 
instrument  carefully  by  the  long  level  of  the  telescope,  using 
in  the  operation  the  tangent  movement  of  the  telescope  axis 
in  connection  with  the  leveling  screws  of  the  parallel  plates 
until  the  bubble  will  remain  in  the  centre  during  a complete 
revolution  of  the  instrument  upon  its  axis. 

Place  the  equatorial  sights  on  the  top  of  the  blocks  as 
closely  as  is  practicable  with  the  distinct  view  of  a distant 
object;  and  having  previously  set  the  declination  arm  at 
zero,  sight  through  the  interval  between  the  equatorial 
sights  and  the  blocks  at  some  definite  point  or  object,  the 
declination  arm  being  placed  over  either  pair  of  the  capstan- 
head  screws  on  the  under  side  of  the  disc. 

Keeping  the  declination  arm  upon  the  object  with  one 
hand,  with  the  other  turn  the  instrument  half  around  on  its 
axis,  and  sight  upon  the  same  object  as  before.  If  the  sight 
strikes  either  above  or  below,  move  the  two  capstan-head 
screws  immediately  under  the  arm,  loosening  one  and  tight- 
ening the  other  as  may  be  needed  until  half  the  error  is 
removed. 

Sight  again  and  repeat  the  operation,  if  needed,  until 
the  sight  will  strike  the  same  object  in  both  positions  of  the 
instrument,  when  the  adjustment  of  the  axis  in  one  direc- 
tion will  be  complete. 

Now  turn  the  instrument  at  right  angles,  keeping  the 
sight  still  upon  the  same  object  as  before;  if  it  strikes  the 
same  point  when  sighted  through,  the  axis  will  be  truly 
vertical  in  the  second  position  of  the  instrument. 

If  not,  bring  the  sight  upon  the  same  point  by  the  other 
pair  of  capstan-head  screws  now  under  the  declination  arc, 
reverse  as  before  and  continue  the  operation  until  the  same 
object  will  keep  in  the  sight  in  all  positions,  when  the  polar 
axis  will  be  made  precisely  at  right  angles  to  the  level  and 
to  the  line  of  collimation  of  the  transit. 


LIGHT  MOUNTAIN  TRANSIT. 


59 


It  should  here  be  noted  that,  as  this  is  by  far  the  most 
delicate  and  important  adjustment  of  the  solar  attachment, 
it  should  be  made  with  the  greatest  care,  the  bubble  kept 
perfectly  in  the  centre  and  frequently  inspected  in  the 
course  of  the  operation. 

(4.)  To  Adjust  the  Hour  Arc.— Whenever  the 
instrument  is  set  in  the  meridian,  as  will  be  hereafter  de- 
scribed, the  index  of  the  hour  arc  should  read  apparent 
time. 

If  not,  loosen  the  two  flat-head  screws  on  the  top  of  the 
hour  circle,  and  with  the  hand  turn  the  circle  around  until 
it  does,  fasten  the  screws  again,  and  the  adjustment  will  be 
complete. 

To  obtain  mean  time,  of  course  the  correction  of  the 
equation  for  the  given  day,  as  given  in  the  Nautical  Alma- 
nac, must  always  be  applied. 

To  find  the  Latitude . 

First  level  the  instrument  very  carefully,  using,  as  before, 
the  level  of  the  telescope  until  the  bubble  will  remain  in 
the  centre  during  a complete  revolution  of  the  instrument, 
the  tangent  movement  of  the  telescope  being  used  in  con- 
nection with  the  leveling  screws  of  the  parallel  plates,  and 
the  axis  of  the  telescope  firmly  clamped. 

Next  clamp  the  vertical  arc,  so  that  its  zero  and  that  of 
irs  vernier  coincide  as  near  as  may  be,  and  then  bring  them 
into  exact  line  by  the  tangent  screw  of  the  vernier. 

Then,  having  the  declination  of  the  sun  for  12  o’clock  of 
the  given  day  as  affected  by  the  meridional  refraction  care- 
fully set  off  upon  the  declination  arc,  note  also  the  equation 
of  time  and  fifteen  or  twenty  minutes  before  noon,  the  tele- 
scope being  directed  to  the  north,  and  the  object-end  lowered 
until,  by  moving  the  instrument  upon  its  spindle  and  the 


60 


LIGHT  MOUNTAIN  TRANSIT. 


declination  arc  from  side  to  side,  the  sun’s  image  is  brought 
nearly  into  position  between  the  equatorial  lines.  Now  bring 
the  declination  arc  directly  in  line  with  the  telescope,  clamp 
the  axis  firmly,  and  with  the  tangent  screw  bring  the  image 
precisely  between  the  lines  and  keep  it  there  with  the  tangent 
screw,  raising  it  as  long  as  it  runs  below  the  lower  equatorial 
line,  or  in  other  words,  as  long  as  the  sun  continues  to  rise 
in  the  heavens. 

When  the  sun  reaches  the  meridian  the  image  will  remain 
stationary  for  an  instant  and  then  begin  to  rise  on  the  plate. 

The  moment  the  image  ceases  to  run  below  is  of  course 
apparent  noon,  when  the  index  of  the  hour  arc  should  in- 
dicate XII,  and  the  latitude  be  determined  by  the  reading 
of  the  vertical  arc. 

It  must  be  remembered,  however,  that  the  angle  through 
which  the  polar  axis  has  moved  in  the  operation  just  de- 
scribed is  measured  from  the  zenith  instead  of  the  horizon 
as  in  the  ordinary  solar,  so  that  the  angle  read  on  the  ver- 
tical limb  is  the  complement  of  the  latitude. 

The  latitude  itself  is  readily  found  by  subtracting  this 
angle  from  90° ; thus  at  Troy,  the  reading  of  the  limb  being 
found  as  above  directed  to  be  47°  16',  the  latitude  will  be 
90° — 47°  16'  =42°  44'. 

The  latitude  may  also  be  read  direct  by  referring  to  the 
inner  row  of  figures  on  the  arc,  beginning  with  90  in  the 
centre,  and  running  to  10  on  either  side. 

It.  M.  Jones 9 Patent  Latitude  Are. 

In  this  new  attachment,  which  has  now  been  secured  ex- 
clusively to  us,  the  usual  vertical  arc  is  omitted,  and  replaced 
by  a double  latitude  arc  attached  to  the  under  side  of  the 
telescope,  as  shown  in  Fig.  11.  The  smaller  arc  having  its 
centre  directly  under  the  cross-bar  of  the  telescope,  has  an 
arm  with  vernier  reading  the  arc  to  single  minutes,  and 


LIGHT  MOUNTAIN  TRANSIT- 


61 


Fig. 11 

Light  Mountain  Solar  Transit,  with  Jones’  Patent  Latitude 
Arc,  and  reversible  level  bubble.  Price  as  shown, 
including  extension  tripod,  - $299.00. 


62 


LIGHT  MOUNTAIN  TRANSIT. 


carries  also  a level  tube  open  both  top  and  bottom,  with  a 
divided  scale  over  each  opening,  in  order  to  read  the  level 
accurately. 

In  obtaining  latitudes  with  this  attachment,  the  declina- 
tion being  set  off  as  usual,  the  level  bubble  should  be 
brought  into  the  centre  of  its  scale  when  the  sun  is  on  the 
meridian. 

The  reading  of  the  smaller  arc  then  gives  the  latitude  of 
the  place,  and  in  all  further  observations  of  the  latitude 
reference  is  made  to  the  level  rather  than  to  the  divisions, 
the  level  being  easily  brought  into  the  centre  of  the  scale, 
thus  enabling  the  surveyor  to  recover  the  latitude  more 
rapidly  than  with  the  ordinary  vertical  arc. 

Minute  changes,  as  long  lines  are  run  either  north  or 
south,  maybe  computed  and  set  off  on  the  larger  arc,  which 
reads  by  its  vernier  to  ten  seconds  of  a degree. 

The  Solar  apparatus  can  also  be  used  when  the  telescope 
is  revolved  and  the  apparatus  brought  below  it,  the  latitude 
being  now  ascertained  by  reference  to  the  other  side  of  the 
level  with  its  divided  scale. 

There  is  but  one  test  required  of  the  adjustment  of  this 
attachment,  viz.  that  both  arcs  should  read  zero,  when  the 
telescope  is  made  horizontal  by  its  long  level,  and  the 
smaller  level  of  the  arc  below  is  also  brought  into  the  centre 
of  its  scale. 

If  not  correct,  they  may  be  adjusted  by  loosening  the 
screws  by  which  each  is  confined,  and  moving  the  arcs  until 
the  zeros  of  both  are  in  coincidence  with  the  zeros  of  their 
verniers,  care  being  also  taken  to  set  up  the  screws  firmly 
again. 


LIGHT  MOUNTAIN  TRANSIT. 


63 


PRICES. 

Jones’  Patent  Latitude  Arc,  with  reversible  level 

bubble $72  00 

When  furnished  with  a new  transit  of  our 
make  in  place  of  the  ordinary  vertical  arc, 
the  Jones’  Patent  Latitude  Arc,  with  revers- 
ible level  bubble,  increases  the  cost  of  the  in- 
strument   54  00 

Thus  : The  Light  Mountain  Transit,  with  Patent 
Solar  Attachment  and  Jones’  Patent  Latitude 
Arc,  costs 299  00 

To  use  the  Solar  Attachment. 

From  the  foregoing  description  it  will  be  readily  under- 
stood, that  good  results  can  not  be  obtained  from  the  solar 
attachment  unless  the  transit  is  of  good  construction — 
furnished  with  the  appliances  of  a level  on  telescope,  clamp 
and  tangent  movement  to  axis,  and  vertical  arc  with  ad- 
justable vernier,  and  the  sockets  or  centres  in  such  condition 
that  the  level  of  the  telescope  will  remain  in  the  centre 
when  the  instrument  is  revolved  upon  either  socket. 

To  run  lines  with  the  Solar  Attachment . 

Having  set  off  the  complement  of  the  latitude  of  the 
place  on  the  vertical  arc,  and  the  declination  for  the 
given  day  and  hour  as  in  the  solar,  the  instrument 
being  also  carefully  leveled  by  the  telescope  bubble, 
set  the  horizontal  limb  at  zero  and  clamp  the  plates 
together,  loosen  the  lower  clamp  so  that  the  transit  moves 
easily  upon  its  lower  socket,  set  the  instrument  approxi- 
mately north  and  south,  the  object  end  of  the  telescope  point- 
ing to  the  north,  turn  the  proper  solar  lens  to  the  sun,  and 
with  one  hand  on  the  plates  and  the  other  on  the  revolv- 
ing arm,  move  them  from  side  to  side  until  the  sun’s  image 


64 


LIGHT  MOUNTAIN  TRANSIT. 


is  brought  between  the  equatorial  lines  on  the  silver 
plate. 

The  lower  clamp  of  the  instrument  should  now  be  fast- 
ened and  any  further  lateral  movement  be  made  by  the 
tangent  screw  of  the  tripod.  The  necessary  allowance  be- 
ing made  for  refraction,  the  telescope  will  be  in  the  true 
meridian,  and  being  unclamped,  may  be  used  like  the  sights 
of  the  ordinary  solar  compass,  but  with  far  greater  accuracy 
and  satisfaction  in  establishing  meridian  lines.  Of  course 
when  the  upper  or  vernier  plate  is  unclamped  from  the  limb, 
any  angle  read  by  the  verniers  is  an  angle  from  the  meridian, 
and  thus  parallels  of  latitude  or  any  other  angles  from  the 
true  meridian  may  be  established  as  with  the  solar  compass. 

The  bearing  of  the  needle,  when  the  telescope  is  on  the 
meridian,  will  also  give  the  variation  of  the  needle  at  the 
point  of  observation. 

If  the  instrument,  as  in  our  surveyors’  transits,  has  a 
movable  compass  circle,  the  variation  of  the  needle  can  be 
set  off  to  single  minutes,  the  needle  kept  at  zero,  or  "with 
the  sun,”  and  thus  lines  be  run  by  the  needle  alone  when 
the  sun  is  obscured. 

The  variation  circle  is  also  applied  to  engineers’  transits 
of  our  make,  when  desired  at  the  time  of  ordering  the 
instrument. 

As  shown  in  the  engraving,  the  cost  of  the  combined 
light  mountain  transit  and  solar  attachment  is  $245. 

The  cost  of  the  solar  attachment,  combined  with  our 
double  vernier  surveyors’  transit,  and  with  the  same  extras, 
will  be  $226.  (See  Fig.  22.) 

Combined  with  the  engineers’  transit,  and  having  a vari- 
ation plate,  $250.  (See  Fig.  8.) 

Where  the  variation  plate  is  desired  in  the  application  of 
the  new  solar  attachment  to  any  engineers’  transit  sent  to  us 
for  the  purpose,  a charge  of  $15  will  be  made  for  the  same. 


LIGHT  MOUNTAIN  TKANSIT. 


65 


Advantages  of  the  Solar  Attachment . 

From  what  has  been  already  said  the  intelligent  surveyor 
will  readily  understand  that  the  more  perfect  horizon  ob- 
tained by  the  use  of  the  telescope  level,  and  the  use  of  a 
telescope  in  place  of  sights,  render  the  new  attachment 
more  accurate  than  the  ordinary  solar  compass. 

It  can  also  be  put  on  the  telescope  of  any  good  transit  at 
comparatively  small  cost,  and  thus  enable  the  surveyor  to 
establish  the  true  meridian,  to  determine  the  correct  lati- 
tude, and  to  obtain  true  time  very  nearly. 

Its  adaptation  to  the  purposes  of  illustration  and  instruc- 
tion in  practical  astronomy  in  colleges  and  schools,  will 
occur  to  every  teacher;  and  we  believe  that  for  the  govern- 
ment surveyor  it  furnishes  a long-sought  and  much-needed 
instrument,  superior,  in  many  respects,  to  the  solar  compass 
now  so  commonly  used. 

In  experiments  made  by  us,  an  error  of  one-quarter  of  a 
minute  in  the  direction  of  the  true  meridian,  or  in  latitude, 
could  be  easily  detected  by  observing  the  sun’s  image  by  a 
magnifier,  and  we  feel  confident  that  any  one  who  uses  the 
new  solar  will  be  surprised  and  delighted  witli  its  work. 
When  desired  it  can  be  removed  from  the  telescope  and 
packed  in  the  instrument  case. 

A thin  sheath  is  put  on  the  polar  axis,  and  kept  in  its 
place  by  the  screw  and  washer  of  the  socket. 

The  weight  of  the  new  solar  attachment  is  but  little  over 
ten  ounces,  and  is  so  distributed  as  not  to  disturb  the 
counterpoise  of  the  instrument,  thus  obviating  the  objection 
which  has  hitherto  prevented  the  successful  application  of 
the  telescope  to  the  solar  apparatus. 

It  is  evident  that  all  transits  to  which  the  solar  attach- 
ment is  to  be  applied  should  have  a horizontal  limb  and 


66 


LIGHT  MOUNTAIN  TRANSIT. 


verniers,  and  be  leveled  by  leveling  screws  and  parallel 
plates. 

It  can,  however,  be  pnt  on  the  telescope  of  our  vernier 
transit  compass,  but  in  that  case  the  angles  taken  from  the 
meridian  will  be  measured  by  the  needle  only. 

Of  course  it  will  be  understood,  in  all  cases,  that  where 
transits  of  any  kind  are  to  be  supplied  with  the  new  solar 
attachment,  they  must  be  in  perfect  order,  especially  in 
respect  to  the  sockets,  before  correct  work  can  be  done. 

Other  Attachments. 

In  the  surveys  of  mines  with  this  and  other  transits,  a 
number  of  appliances  are  used,  which  may  now  be  described. 

The  reflector,  Fig.  12,  is  an  elliptical  piece 
of  brass,  silver-plated  on  the  under  side, 
and  inclined  at  an  angle  of  45°  to  its  ring, 
which  is  fitted  to  the  object  end  of  the 
telescope ; the  hole  in  the  reflector  admits 
the  use  of  the  telescope,  while  a light  held 
near  the  under  surface  illuminates  the  cross-wires.  Price 
of  reflector  is  $4.00. 

The  diagonal  prism,  Fig.  13,  used  where 
greater  vertical  angles  are  to  be  taken  than 
are  possible  with  the  ordinary  telescope, 
consists  merely  of  a diagonal  prism  attached 
to  the  cap  of  the  eye-piece,  by  which  the 
object  is  reflected  to  the  eye,  placed  at 
right  angles  to  the  telescope ; when  di- 
rected to  the  sun  the  little  slide  or  darkener  containing 
colored  glass  is  moved  over  the  opening. 

The  circular  plate  with  which  the  prism  is  connected  is 
made  to  turn  in  the  cap  so  that  when  it  is  substituted  for 
the  ordinary  cap  of  the  eye-piece,  the  opening  over  the  prism 
can  be  easily  adjusted  to  the  position  of  the  eye. 


Fig.  12. 


LIGHT  MOUNTAIN  TRANSIT. 


67 


An  angle  of  sixty  degrees  elevation  can  thus  be  taken 
with  the  prism.  Price  of  diagonal  prism  is  $8.00. 


EXTRA  TELESCOPES  FOR  VERTICAL  SIGHTING. 


A common  ar- 
rangement for 
sighting  up  or 
down  a vertical 
shaft  is  shown  in 
Fig.  14,  in  which 
an  extra  telescope 
is  fitted  by  a coni- 
cal spindle  or,  as  is 
now  our  practice, 
by  a flange  and 
disc  connecting  it 
with  the  axis,  so 
as  to  make  it.  pre- 
cisely parallel  to 
the  centre  tele- 
scope; a counter- 
poise, as  shown,  is 
fitted  to  the  other 
end,  and  both 
can  be  detached 
at  pleasure,  and 
placed  in  the 
packing-case  when 
not  in  use. 

In  Fig.  15,  the 
extra  telescope  is 
connected  with  the 
main  one  by  coup- 


68 


LIGHT  MOUNTAIN  TRANSIT. 


ling  nuts,  which  fasten  it  securely  directly  over  the  centre 
of  the  instrument,  and  allow  its  ready  removal  and  replace- 
ment without  disturbing  its  adjustments. 

It  will  be  understood  that  in  both 
arrangements  the  extra  telescopes  are 
adjusted  to  the  main  telescopes  of  the 
transits,  so  that  the  line  of  collimation  of 
both  are  parallel,  and  in  the  same  plane, 
horizontal  in  Fig.  14,  and  vertical  in  Fig. 
15 ; and  in  both,  the  extra  telescope 
swings  over  the  outside  of  the  transit 
plates.  The  diagonal  prism  is  often  used 
with  the  extra  telescope  for  greater  con- 
venience in  sighting.  Price  of  the  extra 
telescopes,  either  Fig.  14  or  15,  $25.00. 


PLUMMET  LAMP. 

As  shown  in  Fig.  16,  this  is  a large 
plummet  of  which  the  upper  part  is  hol- 
low, to  contain  oil ; and  has  also  a tube 
for  wick  covered  by  a screw  cap. 

It  is  hung  in  gimbals  by  a chain  with 
hook,  and  so  always  assumes  a vertical 
position,  and  when  suspended  from  a tri- 
pod with  shifting  centre,  can  be  easily 
adjusted  over  a given  point. 

Fig.  16.  Two  of  these  lamps  are  often  packed  in 

a simple  wooden  case,  furnished  with  a 
strap  to  sling  over  the  shoulders ; the  weight  of  each  lamp 
is  about  one  and  a quarter  pounds.  Price  of  each  lamp  as 
shown,  $10.00, 


LIGHT  MOUNTAIN  TRANSIT, 


69 


EXTENSION  TRIPOD. 


Fig.  17. 


The  Light  Mountain  Transit  is  almost  always  used  upon 
our  patent  extension  tripod,  Pig.  17,  in  which  all  its  legs  can 
be  shortened  or  lengthened  at  will.  It  is  thus  adapted  for 


70 


LIGHT  MOUNTAIN  TRANSIT. 


use  in  mountain  surveys,  where  one  or  more  legs  must  be 
shortened;  or  for  mines,  where  in  many  places  a short 
tripod  is  indispensable. 

If  desired,  the  sliding  pieces  can  be  easily  turned  end  for 
end,  the  points  being  thus  put  out  of  the  way,  and  the  tri- 
pod more  safely  transported.  The  tripod  when  closed  is 
only  three  feet  long,  and  is  carried  by  an  ordinary  shawl- 
strap.  Price  as  shown  $15.00. 


GRADIENTER. 


Price  as  shown  $18.00.  (See  No.  45  in  Price  List.) 

This  attachment,  as  shown  in  Fig.  18,  is  often  used  with 
this  and  other  transits  for  fixing  grades,  determining  dis- 
tances, etc. 

It  consists  mainly  of  a screw  attached  to  the  semicircu- 


LIGHT  MOUNTAIN  TRANSIT. 


71 


lar  expanded  arm  of  the  ordinary  clamp  of  the  telescope 
axis;  the  screw  is  accurately  cut  to  a given  number  of 
threads,  and  passing  through  a nut  in  one  side  of  the  arm, 
presses  against  a little  stud,  A,  fixed  to  the  inside  surface 
of  the  right-hand  standard. 

In  the  other  side  of  the  semicircular  arm  is  inserted  a 
hollow  cylinder  containing  a pin  actuated  by  a strong  spiral 
spring,  the  end  of  the  pin  pressing  against  the  side  of  the 
stud  opposite  that  in  contact  with  the  screw. 

Near  the  other  end  of  the  screw,  and  turning  with  it,  is 
a wheel,  or  micrometer,  the  rim  of  which  is  plated  with 
silver,  and  divided  into  one  hundred  equal  parts. 

A small  silver  scale,  attached  to  the  arm  and  just  above 
the  micrometer  wheel,  is  divided  into  spaces,  each  of  wThich 
is  just  equal  to  one  revolution  of  the  screw  ; so  that  by  com- 
paring the  edge  of  the  wheel  with  the  divisions-  of  the 
scale,  the  number  of  complete  revolutions  of  the  screw  can 
be  easily  counted. 

It  will  be  seen  that  when  the  clamp  is  made  fast  to  the 
axis  by  the  clamp-screw,  and  the  gradienter-screw  turned, 
it  will  move  the  telescope  vertically,  precisely  like  the  tan- 
gent-screw ordinarily  used. 

And  as  the  value  of  a thread  is  such  that  a complete 
revolution  of  the  screw  will  move  the  horizontal  cross-wire 
of  the  telescope  over  a space  of  one  foot  on  a rod  at  a dis- 
tance of  one  hundred  feet,  it  is  clear  that  when  the  screw 
is  turned  through  fifty  spaces  on  the  graduated  head,  the 
wire  will  pass  over  fifty  one-hundredths,  or  one-half  a foot 
on  the  rod,  and  so  on  in  the  same  proportion. 

In  this  way  the  Gradienter  can  be  used  in  the  measure- 
ment of  distances,  precisely  like  the  stadia  already  described 
in  the  article  on  the  Engineers’  Transit. 

Grades  can  also  be  established,  with  great  facility,  as  fol- 
lows : First,  level  the  instrument ; bring  the  telescope  level 


72 


LIGHT  MOUNTAIN  TRANSIT. 


to  its  centre  by  the  clamp  and  gradienter  screw  ; move  the 
graduated  head  until  its  zero  is  brought  to  the  edge  of  the 
scale;  and  then  turn  off  as  many  spaces  on  the  head  as 
there  are  hundredths  of  feet  to  the  hundred  in  the  grade  to 
be  established. 

Weight  of  the  Mountain  Transit. 

The  weight  of  this  instrument  with  plain  telescope,  and 
without  tripod,  is  8-J-  pounds  ; with  solar  attachment,  arc, 
level,  and  clamp,  as  shown  in  figure,  9^  pounds.  The 
extension  tripod  weighs  about  8 pounds. 

Leather  Case. — Besides  the  light  mahogany  box,  in 
which  the  instrument  is  packed  as  usual,  there  is  also  sup- 
plied a light  sole-leather  case,  amply  furnished  with  straps 
for  “ packing.” 

The  Light  Mountain  Transit  was  introduced  by  us  in 
1876  to  meet  a demand  for  a light  instrument  of  the  finest 
quality. 

It  has  met  with  a very  large  sale,  and  been  universally 
approved. 

We  commend  it  with  perfect  confidence  to  all,  as  a tran- 
sit of  first  quality,  adapted  to  all  kinds  of  work  which  may 
be  required,  and  especially  fitted  for  mining  or  mountain 
surveying,  where  great  portability  is  desired. 


THE  SURVEYORS*  TRANSIT. 

THE  SURVEYORS5  TRANSIT. 


Price  as  shown,  5 or  5-|-in.  needle,  including  tripod,  $160.00. 

The  Surveyors’  Transit  has  essentially  the  same  construc- 
tion as  the  instrument  first  described  in  the  manual,  but 
its  compass-circle  is  movable  about  its  centre,  like  that  of 


74 


THE  SURVEYORS’  TRANSIT. 


the  Mountain  Transit,  in  order  that  the  variation  of  the 
needle  may  be  set  off  in  the  surveys  of  old  lines,  or  in  run- 
ning lines  by  the  true  meridian. 

The  arrangement  of  the  sockets  and  leveling  head,  how- 
ever, permits  the  Surveyors’  Transit  to  be  detached  from 
the  leveling  head,  packed  separately  in  the  case,  and  re- 
placed, when  desired,  upon  its  spindle,  without  in  any  way 
disturbing  its  adjustments. 


Fig.  20. 


The  sectional  view,  Fig,  20,  shows  the  interior  construc- 
tion of  the  sockets  of  the  transit,  the  manner  in  which  it 
is  detached  from  the  spindle,  and  the  means  by  which  it 
can  be  taken  apart  if  desired. 

In  the  figure,  the  limb  B B is  attached  to  the  main 
socket  of  L L,  which  is  itself  carefully  fitted  to  the  conical 
spindle  P,  and  held  in  place  by  the  spring  catch  C. 

The  upper  plate,  A A,  carrying  the  compass-circle, 


THE  SURVEYORS*  TRANSIT. 


75 


standards,  &c.,  is  fastened  to  the  flanges  of  the  socket, U U, 
which  is  fitted  to  the  upper  conical  surface  of  the  main 
socket  L;  the  weight  of  all  the  parts  being  supported  on 
the  small  bearings  of  the  end  of  the  socket,  as  shown,  so  as 
to  turn  with  the  least  possible  friction. 

A small  conical  centre,  in  which  from  below  is  inserted 
the  strong  screw,  S,  is  brought  down  firmly  upon  the  upper 
end  of  the  main  socket  L L,  and  thus  holds  the  two  plates 
of  the  instrument  securely  together,  while  at  the  same  time 
allowing  them  to  move  freely  around  each  other  in  use. 

A small  disc  above  the  conical  centre  contains  the  steel 
centre-pin  upon  which  rests  the  needle,  as  shown ; the  disc 
is  fastened  to  the  upper  plate  by  two  small  screws,  as  repre- 
sented. 

The  main  socket  with  all  its  parts  is  of  the  best  bell-metal 
and  is  most  carefully  and  thoroughly  made,  the  long  bear- 
ing of  the  sockets  ensuring  their  firm  and  easy  movement, 
while  at  the  same  time  they  are  entirely  out  of  the  reach 
of  dust,  or  other  source  of  wear. 

When  desired  the  whole  upper  part  of  the  instrument  can 
be  taken  off  from  the  spindle  by  pulling  out  the  head  of 
the  spring-catch  at  C,  and  when  replaced  will  be  secured  by 
the  self-acting  spring  of  the  catch. 

The  figure  also  shows  the  covers  of  the  leveling  screws, 
the  shifting  centre  of  the  lower  leveling  plate,  and  the  screw 
and  loop  for  the  attachment  of  the  plummet. 

To  Take  Apart  the  Surveyors’  Transit . 

When  it  is  necessary  to  separate  the  plates  of  the  transit 
proceed  as  follows : 

(1)  Remove  the  clamp-screw  and  take  off  the  head  of  the 
pinion,  both  on  the  north  end  and  outside  the  compass 
circle.  (2)  Unscrew  the  bezel  ring  containing  the  glass 
cover  of  the  compass,  remove  the  needle  and  button 


76 


THE  SURVEYORS’  TRANSIT. 


beneath  it,  and  take  out  the  two  small  screws  so  as  to  remove 
the  disc.  (3)  Take  the  instrument  from  its  spindle,  and 
with  a large  screw-driver  take  out  the  screw  S from  the 
underside  of  the  conical  centre,  Fig.  16.  (4)  Drive  out  the 

centre  from  below  by  a round  piece  of  wood,  holding  the 
instrument  vertical  so  that  the  centre  will  not  bruise  the 
circle.  (5)  Set  the  instrument  again  upon  its  spindle,  take 
out  the  clamp-screw  to  the  tangent  movement  of  the  limb, 
and  the  work  is  complete.  To  put  the  transit  together  again, 
proceed  exactly  the  reverse  of  the  operation  thus  described. 

Attachments  or  Transit. 

In  the  engraving  the  telescope  is  shown  with  the  vertical 
circle,  level,  and  clamp  and  tangent,  and  one  or  all  of  these 
extra  attachments  are  often  applied  to  this  and  the  other 
transits  described. 

The  Vertical  Circle  firmly  secured  to  the  axis  of  the 
telescope  is  4|-  inches  diameter,  plated  with  silver,  divided 
to  half  degrees,  and  with  its  vernier  enables  the  surveyor  to 
obtain  vertical  angles  to  single  minutes. 

The  Level  on  Telescope  consists  of  a brass  tube 
about  6-J-  inches  long,  each  end  of  which  is  held  between  two 
capstan-nuts  connected  with  a screw  or  stem  attached  to  the 
under  side  of  the  telescope  tube. 

The  vial  enclosed  in  the  tube  is  a little  over  5 inches  long 
and  half  an  inch  in  diameter,  is  ground  on  its  upper  interior 
surface  so  as  to  ensure  an  even  and  sensitive  bubble,  the 
length  of  which  is  measured  by  the  divided  scale  above ; 
the  scale  is  divided  into  tenths  of  an  inch,  and  figured  from 
0 at  the  centre  to  5,  10,  15,  20,  on  either  side,  and  thus 
determines  when  the  bubble  is  brought  into  the  centre  of 
its  run. 

The  Clamp  and  Tangent  consists  of  an  arm  at  one 
end  encircling  the  telescope  axis,  and  at  the  other  connected 
with  the  tangent-screw ; the  clamp  is  fastened  at  will  to  the 


THE  SURVEYORS’  TRANSIT. 


7] 


axis  by  a clamp-screw  as  shown  in  Fig.  20,  inserted  at  one 
side  of  the  ring,  and  then  by  turning  the  tangent-screw  the 
telescope  is  raised  or  lowered  as  desired. 

The  clamp  and  tangent  ought  always  to  accompany  the 
vertical  circle,  and  level  on  telescope,  whenever  either  is 
applied  to  a transit. 

The  Adjustments  of  this  instrument  so  far  as  relates 
to  the  levels,  needle,  line  of  collimation,  &c.,  are  the  same  as 
those  of  the  Engineers’  Transit,  and  we  need  to  mention 
only  those  of  the  attachments. 

To  Adjust  the  Vertical  Circle. 

Having  the  instrument  firmly  set  up  and  carefully  leveled, 
bring  into  line  the  zeros  of  the  circle  and  vernier,  and  with 
the  telescope  find  or  place  some  well-defined  point  or  line, 
from  one  hundred  to  five  hundred  feet  distant,  which  is  cut 
by  the  horizontal  wire. 

Turn  the  instrument  half-way  around,  revolve  the  tele- 
scope, and  fixing  the  wire  upon  the  same  point  as  before, 
note  if  the  zeros  are  again  in  line. 

If  not,  loosen  the  capstan-head  screws,  which  fasten  the 
vernier,  and  move  the  zero  of  the  vernier  over  half  the  error; 
bring  the  zeros  again  into  coincidence,  and  proceed  precisely 
as  at  first,  until  the  error  is  entirely  corrected,  when  the 
adjustment  will  be  complete. 

A slight  error  may  be  most  readily  removed  by  putting 
the  zeros  in  line  and  then  moving  the  wire  itself  over  half 
the  interval. 

The  Level  is  Adjusted  by  bringing  the  bubble  care- 
fully into  the  centre  by  the  nuts  at  each  end  ; and  when 
there  is  a vertical  circle  on  the  instrument,  this  should  be 
done  when  the  zeros  of  circle  and  vernier  are  in  line,  and  in 
adjustment ; when  there  is  no  vertical  circle,  proceed  as 
described  in  the  account  of  the  next  instrument. 


78 


THE  SURVEYORS’  TRANSIT. 


The  Surveyors’  Transit  with  One  Vernier  to 
Limb 


Price  as  shown,  5 or  5-J-in.  needle,  including  tripod,  $133.00. 

is  a modification  of  the  transit  just  described,  in  which 
there  is  but  one  double  vernier  to  limb  and  a different 
arrangement  of  the  sockets,  as  shown  in  the  following  cut. 

The  instrument  is  more  compact  and  somewhat  lighter 
than  that  with  two  verniers,  and  is  furnished  at  less  cost. 
Its  graduations,  telescope  and  attachments  are  all  equal  to 


THE  SURVEYORS’  TRANSIT. 


79 


those  of  the  best  transits,  and  after  an  experience  of  twenty 
years  the  instrument  has  proved  itself  in  every  way  efficient 
and  satisfactory  for  all  classes  of  work. 


In  Fig.  21|  is  shown  the  peculiar  arrangement  of  the 
sockets  of  this  instrument. 

The  main  socket  LL  now,  in  a single  piece,  is  fitted  to 
the  spindle  P,  and  secured  by  a spring  catch  C.  The 
socket,  UTT,  is  formed  in  the  metal  of  the  plates  them- 
selves, a strong  washer  as  shown  above  keeping  them 
securely  together,  but  at  the  same  time  allowing  them  to 
turn  freely  around  each  other. 

The  vernier  with  the  opening  above  is  shown  on  the 
left  at  A.  The  arrangement  of  the  centre-pin,  needle, 
&c.,  is  precisely  like  that  of  the  transit  with  two  verniers, 
and  the  instrument  is  detached  from  the  leveling-head  and 
replaced  in  the  same  manner. 

This  instrument  may  be  taken  apart  by  first  removing  the 
pinion-head  and  clamp-screw,  near  the  north  end  of  the 


80 


THE  SURVEYORS’  TRANSIT. 


compass  circle,  then  unscrewing  the  bezel  ring,  taking  out 
the  needle  and  button  underneath,  and  next  removing  the 
disc  in  which  the  centre-pin  is  fixed,  by  taking  out  two 
small  screws  which  confine  it. 

The  four  screws  which  hold  the  washer  to  the  under- 
plate must  then  be  removed,  and  when  the  clamp-screw  is 
taken  out  the  plates  can  be  separated. 

The  replacing  the  several  parts  is  done  in  the  same  man- 
ner, but  in  a reverse  order. 

The  Adjustments  and  use  of  this  instrument  are 
precisely  like  those  of  the  others  already  described,  and  its 
attachments  to  the  telescope  the  same,  if  desired. 

In  Fig.  21|-  it  is  represented  with  a level  on  telescope, 
with  clamp  and  tangent  to  axis,  an  arrangement  very  gen- 
erally selected,  and  of  which  we  will  now  give  the  adjust- 
ment. 

To  Adjust  the  Level  on  Telescope . — Two  methods 
will  be  given,  of  which  the  first  is  to  be  preferred. 

1.  First  level  the  instrument  carefully,  and  with  the 
clamp  and  tangent  movement  to  the  axis,  make  the  tele- 
scope horizontal,  as  near  as  may  be,  with  the  eye;  then, 
having  the  line  of  collimation  previously  adjusted,  drive  a 
stake  at  a convenient  distance,  say  from  one  hundred  to 
three  hundred  feet,  and  note  the  height  cut  by  the  hori- 
zontal wire,  upon  a staff  set  on  the  top  of  the  stake. 

Fix  another  stake  in  the  opposite  direction,  and  at  the 
same  distance  from  the  instrument,  and  without  disturb- 
ing the  telescope,  turn  the  instrument  upon  its  spindle,  set 
the  staff  upon  the  stake,  and  drive  in  the  ground,  until  the 
same  height  is  indicated  as  in  the  first  observation. 

The  top  of  the  two  stakes  will  then  be  in  the  same  hori- 
zontal line,  however  much  the  telescope  may  be  out  of 
level. 

Now  remove  the  instrument  from  fifty  to  one  hundred 


THE  SURVE YOBS*  TRANSIT. 


81 


feet  to  one  side  of  either  of  the  stakes,  and  in  line  with 
both  ; again  level  the  instrument,  clamp  the  telescope  as 
nearly  horizontal  as  may  be,  and  note  the  heights  indicated 
upon  the  staff  placed  first  upon  the  nearest,  and  then  upon 
the  most  distant  stake. 

If  both  agree,  the  telescope  is  level ; if  they  do  not  agree, 
then  with  the  tangent-screw  move  the  wire  over  nearly  the 
whole  error,  as  shown  at  the  distant  stake,  and  repeat  the 
observation  as  just  described.  Proceed  thus  until  the  hori- 
zontal wire  will  indicate  the  same  height  at  both  stakes, 
when  the  telescope  will  be  truly  horizontal. 

Taking  care  not  to  disturb  its  position,  bring  the  bubble 
into  the  centre  by  the  little  leveling  nuts  at  the  end  of  the 
tube,  when  the  adjustment  will  be  completed. 

2.  Choose  a piece  of  ground  nearly  level,  and  having  set 
the  instrument  firmly,  level  the  plates  carefully,  and  bring 
the  bubble  of  the  telescope  into  the  centre  with  the  tangent- 
screw.  Measure  in  any  direction  from  the  instrument,  from 
one  hundred  to  three  hundred  feet,  and  driye  a stake,  and 
on  the  stake  set  a staff  and  note  the  height  cut  by  the  hori- 
zontal wire  ; then  take  the  same  distance  from  the  instru- 
ment in  an  opposite  direction,  and  drive  another  stake. 

On  that  stake  set  the  staff,  and  note  the  height  cut  by  the 
wire  when  the  telescope  is  turned  m that  direction. 

The  difference  of  the  two  observations  is  evidently  the 
difference  of  level  of  the  two  stakes. 

Set  the  instrument  over  the  lowest  stake,  or  that  upon 
which  the  greatest  height  was  indicated,  and  bring  the 
levels  on  the  plates  and  telescope  into  adjustment  as  at 
first. 

Then,  with  the  staff,  measure  the  perpendicular  distance 
from  the  top  of  the  stake  to  the  centre  of  one  of  the  hori- 
zontal cross-wire  screw-heads;  from  that  distance  subtract 
the  difference  of  level  between  the  two  stakes  and  mark  the 


82 


THE  SURVEYORS'  TRANSIT. 


point  on  the  staff  thus  found  ; place  the  staff  on  the  other 
stake,  and  with  the  tangent-screw  bring  the  horizontal  wire 
to  the  mark  just  found,  and  the  line  will  be  level. 

The  telescope  now  being  level,  bring  the  bubble  of  the 
level  into  the  centre,  by  turning  the  little  nuts  at  the  end 
of  the  tube,  and  noting  again  if  the  wires  cut  the  point  on 
the  staff ; screw  up  the  nuts  firmly  and  the  adjustment  will 
be  completed. 

With  such  a level  carefully  adjusted,  the  engineer,  by 
taking  equal  fore  and  back  sights,  can  run  horizontal  lines 
with  great  rapidity,  and  a good  degree  of  accuracy. 

The  Surveyors’  Transit,  with  its  peculiar  construction  of 
sockets,  &c.,  is  entirely  of  our  own  invention  ; it  has  stood 
the  test  of  over  twenty  years  use,  and  combining,  as  it 
does,  the  capabilities  of  a needle  instrument  with  a fine 
telescope,  and  the  accuracy  of  a divided  limb  and  verniers, 
together  with  a movable  compass-circle  for  setting  off  the 
variation  of  the  needle,  it  is,  for  a mixed  practice  of  accu- 
rate surveying  and  engineering,  the  best  instrument  ever 
constructed. 

Sizes  and  Weights  of  the  Surveyors’  Transit,  with 
plain  telescope,  all  having  two  verniers  to  limb, 

4-in.  needle,  with  leveling-head,  but  no  tripod,  about  12f  lbs. 
5 “ (i  “ “ 15-J  (i 

5i  « « “ “ 16J  " 

With  one  vernier  to  limb, 

4-in.  needle,  with  leveling-head,  but  no  tripod,  about  Ilf  lbs. 
5 « « “ “ 15  “ 

51'  <<  “ “ (£  16f  “ 

Weight  of  the  Attachments , 

Vertical  circle,  4^-in >,  with  vernier,  oz. 

Level  on  telescope,  . . . 8 “ 

Clamp  and  tangent  to  axis,  • . 4 ^ 

4 


the  surve^TTKS^trahsit. 


83 


Fig.  22. 

Surveyors’  Transit  with  Solar  Attachment. 

Price  as  shown,  with  one  vernier  to  limb,  5-inch  needle,  in- 
cluding tripod,  $211.00. 

If  with  two  verniers  to  limb,  $226.00. 


84: 


SURVEYORS'  TRANSITS. 


SURVEYORS’  TRANSIT  WITH  SOLAR  ATTACH- 
MENT. 

The  cut  on  preceding  page  represents  our  Surveyors’ 
Transit  with  one  vernier  to  limb  and  5 inch  needle,  to 
which  is  adapted  the  Solar  Attachment  with  vertical  arc, 
level,  etc. ; both  the  vertical  arc  and  that  of  the  declination 
arm  being  divided  on  silver  and  reading  to  thirty  seconds. 

The  Surveyors’  Transit  with  two  verniers  to  limb  is  also 
arranged  in  precisely  the  same  manner,  when  desired ; but 
the  level,  which  is  shown  above  on  the  plate,  is  then  raised 
and  fitted  to  the  standards,  so  as  to  allow  of  the  vernier 
opening  beneath. 

Both  styles,  represented  and  described  herewith,  have 
been  for  years  in  successful  use  in  different  parts  of  the 
country;  the  prices  of  each  will  be  found  respectively  in 
Price  List,  Nos.  24  and  16 ; both  have  shifting  centres  to 
tripod. 


VERNIER  TRANSIT  COMPASS. 


85 


VERNIER  TRANSIT  COMPASS. 


Price  as  shown,  with  6-inch  needle  and  tripod,  $101.00. 

This  is  essentially  a Vernier  Compass  supplied  with  a 
telescope  in  place  of  the  ordinary  sight-vanes,  thus  giving 
the  surveyor  the  means  of  taking  long  sights,  either  on 
a level,  or  on  hilly  ground,  with  much  greater  ease  and 
accuracy. 

The  telescope  can  also  be  supplied  with  the  extra  attach- 


86 


VERKIER  TRANSIT  COMPASS. 


ments,  as  shown,  and  levels  and  angles  of  elevation  and 
depression  taken,  as  with  the  more  expensive  instruments. 

The  telescopes  are  eleven  inches  long  in  the  larger  sizes 
of  these  instruments,  but  in  the  4-inch,  only  eight  inches ; 
but  all  are  of  fine  quality. 

The  compass-circle  is  moved  about  its  centre  by  a pinion 
placed  underneath  the  circular  plate ; the  variation  of  the 
needle  being  set  off  to  single  minutes  upon  a divided  arc 
attached  to  the  plate  as  shown  in  the  cut;  there  is  also  a 
clamp-screw  by  which  the  circle  is  made  fast. 

The  figure  represents  the  instrument  with  6-inch  needle  ; 
in  the  smaller  sizes,  the  vernier  of  the  compass-circle  is 
within  the  box  and  under  the  glass,  as  with  that  of  the 
Surveyors’  Transit. 

The  needle  lifting-screw  is  also  underneath  the  plate,  but 
concealed  in  the  cut. 

The  Clamp-screw , by  which  the  instrument  is  fixed 
to  the  spindle,  and  the  spring-catch  which  secures  it,  are 
both  shown  on  opposite  sides  of  the  socket. 

The  levels  are  both  above  the  plate,  and  made  adjustable 
by  a capstan-head  screw  at  either  end. 

The  instrument  is  commonly  used  on 
a ball  spindle  placed  in  a compass  tripod 
as  shown  in  Fig.  23,  but  is  sometimes 
fitted  to  a leveling-head  like  that  of  the 
Surveyors’  Transit. 

Compound  Ball . — We  also  manu- 
facture what  may  be  termed  a “ com- 
pound ball-spindle,”  which  has  a tan- 
gent movement,  and  gives  all  the  per- 
fection of  more  costly  arrangements,  at 
a very  moderate  expense.  (Price,  $6.00.) 

As  represented  in  the  cut,  it  has  an 
interior  spindle,  around  which  an  out- 


VERNIER  TRANSIT  COMPASS. 


87 


side  hollow  cylinder  is  moved  by  turning  the  double-headed 
tangent-screw,  which  has  in  the  middle  an  endless  screw, 
working  into  teeth  cut  spirally  around  in  a groove  of  the 
cylinder.  The  compass,  or  other  instrument,  revolves  on 
the  outside  socket,  precisely  as  if  placed  on  a common  ball- 
spindle;  but  when  a slower  movement  is  required,  can  be 
made  fast  by  the  clamp-screw,  and  then  turned  gradually 
around  the  interior  spindle  by  the  tangent-screw,  until  the 
slot  of  the  sight  or  the  intersection  of  the  wires,  is  made 
to  bisect  the  object  with  the  utmost  certainty. 

The  Vernier  Transit  Compass  is  used  either  with  a plain 
telescope,  or  supplied  with  the  extra  attachments  of  vertical 
circle,  level,  &c. ; the  vertical  circle  shown  in  Fig.  23  is 
three  and  a half  inches  in  diameter,  plated  with  silver, 
divided  to  degrees,  and  reads  by  the  vernier  to  five  minutes. 

The  adjustments  of  this  instrument  are  mainly  those  of 
the  transits  already  described. 

In  Surveying  with  this  instrument  the  operator 
should  keep  the  south  end  of  the  compass  circle  towards 
his  person,  read  the  bearings  of  lines  from  the  north  end 
of  the  needle,  and  use  the  telescope  in  place  of  sights, 
revolving  it  as  objects  are  selected  in  opposite  direc- 
tions. 

Before  an  observation  is  taken  the  eye-piece  must  be 
brought  into  distinct  focus  upon  the  cross-wires,  and  the 
object-glass  moved  by  the  pinion-head  until  the  object  is 
brought  into  clear  view,  so  that  the  wires  appear  as  if 
fastened  to  its  surface. 

The  intersection  of  the  wires  being  the  means  by  which 
the  optical  axis  of  the  telescope  is  defined,  should  be  brought 
precisely  upon  the  centre  of  the  object. 

Sizes  and  Weights . 

We  make  three  sizes  of  this  instrument,  having  respec- 


88 


VERNIER  TRANSIT  COMPASS. 


tively  4,  5,  and  6-inch  needles,  the  average  weights  of  which 
are  as  follows  : 

4- incli  needle,  plain  telescope,  and  without  tripod,  5 lbs. 

5- incli  “ “ “ “ “ 8^  “ 

6- inch  “ “ “ “ “ 11  “ 

THE  SOLAR  COMPASS. 

This  instrument,  so  ingeniously  contrived  for  readily 
determining  a true  meridian  or  north  and  south  line,  was 
invented  by  William  A.  Burt,  of  Michigan,  and  patented 
by  him  in  1836.  It  has  since  come  into  general  use  in  the 
surveys  of  U.  S.  public  lands,  the  principal  lines  of  which 
are  required  to  be  run  with  reference  to  the  true  meridian. 

The  invention  has  long  since  become  public  property, 
and  for  over  twenty  years  the  Solar  Compass  has  been 
manufactured  by  us,  with  improvements  of  our  own,  which 
have  made  it  increasingly  popular  and  efficient. 

The  arrangement  of  its  sockets  and  plates  is  similar  to 
that  of  the  Surveyors’  Transit,  as  shown  in  Fig.  20,  except 
that  the  sight  vanes  are  attached  to  the  under  plate  or 
limb,  and  this  revolves  around  the  upper  or  vernier  plate 
on  which  the  solar  apparatus  is  placed. 

The  limb  is  divided  to  half  degrees,  is  figured  in  two 
rows,  as  usual,  and  reads  by  the  two  opposite  verniers  to 
single  minutes. 

The  divisions  of  the  limb  and  all  other  arcs  of  the  Solar 
Compass  are  made  upon  solid  silver  so  as  to  avoid  tarnishing. 

The  Solar  Apparatus. 

The  Solar  Apparatus  is  seen  in  the  place  of  the  needle, 
and  in  fact  operates  as  its  substitute  in  the  field. 

It  consists  mainly  of  three  arcs  of  circles,  by  which  can 
be  set  off  the  latitude  of  a place,  the  declination  of  the  sun, 
and  the  hour  of  the  day. 

These  arcs,  designated  in  the  cut  by  the  letters  a , 5,  and 


THE  SOLA R COMPASS, 


89 


Fig.  25. 

Price  as  shown,  including  leveling  adopter,  compound 
tangent  ball,  and  leveling  tripod,  $210.00. 


90 


THE  SOLAR  COMPASS. 


c,  are  therefore  termed  the  latitude,  the  declination,  and  the 
hour  arcs  respectively. 

The  Latitude  Arc,  a , has  its  centre  of  motion  in  two 
pivots,  one  of  which  is  seen  at  d , the  other  is  concealed  in 
the  cut. 

It  is  moved  either  up  or  down  within  a hollow  arc,  seen 
in  the  cut,  by  a tangent-screw  at  /,  and  is  securely  fastened 
in  any  position  by  a clamp-screw. 

The  Latitude  arc  is  graduated  to  quarter  degrees,  and 
reads  by  its  vernier,  e,  to  single  minutes  ; it  has  a range  of 
about  thirty-five  degrees,  so  as  to  be  adjustable  to  the  lati- 
tude of  any  place  in  the  United  States. 

The  Declination  Arc,  b,  is  also  graduated  to  quarter 
degrees,  and  has  a range  of  about  twenty-eight  degrees. 

Its  vernier,  v,  reading  to  single  minutes,  is  fixed  to  a 
movable  arm,  h , having  its  centre  of  motion  at  the  end 
of  the  declination  arc  at  g\  the  arm  is  moved  over  the  sur- 
face of  the  declination  arc,  and  its  vernier  set  to  any  reading 
by  turning  the  head  of  the  tangent-screw,  Jc.  It  is  also 
securely  clamped  in  any  position  by  a screw,  concealed  in 
the  engraving. 

Solar  Lenses  and  Lines . — At  each  end  of  the  arm, 
h , is  a rectangular  block  of  brass,  in  which  is  set  a small 
convex  lens,  having  its  focus  on  the  surface  of  a little  silver 
plate  A,  Fig.  26,  fastened  by  screws  to  the  inside  of  the 
opposite  block. 

On  the  surface  of  the  plate  are  marked 
two  sets  of  lines  intersecting  each  other 
at  right  angles ; of  these  b b are  termed 
the  hour  lines,  and  c c the  equatorial  lines, 
as  having  reference  respectively  to  the 
hour  of  the  day  and  the  position  of  the  sun  in  relation  to  the 
equator. 


Fig.  26. 


THE  SOLAR  COMPASS. 


91 


In  Fig.  25  the  equatorial  lines  are  those  on  the  lower 
block;  parallel  to  the  surface  of  the  hour  arc  c ; the  hour 
lines  are  of  course  those  at  right  angles  to  the  first. 

Equatorial  Sights. — On  the  top  of  each  of  the  rect- 
angular blocks  is  seen  a little  sighting-piece,  termed  the 
equatorial  sight,  fastened  to  the  block  by  a small  milled 
head-screw,  so  as  to  be  detached  at  pleasure. 

They  are  used,  as  will  be  explained  hereafter,  in  adjusting 
the  different  parts  of  the  solar  apparatus. 

The  Hour  Arc 9 c,  is  supported  by  the  two  pivots  of 
the  latitude  arc,  already  spoken  of,  and  is  also  connected 
with  that  arc  by  a curved  arm,  as  shown  in  the  figure. 

The  hour  arc  has  a range  of  about  120°,  is  divided  to  half 
degrees,  and  figured  in  two  series,  designating  both  the 
hours  and  the  degrees,  the  middle  division  being  marked  12 
and  90  on  either  side  of  the  graduated  lines. 

The  Polar  Axis . — Through  the  centre  of  the  hour 
arc  passes  a hollow  socket,  p,  containing  the  spindle  of  the 
declination  arc,  by  means  of  which  this  arc  can  bo  moved 
from  side  to  side  over  the  surface  of  the  hour  arc,  or  turned 
completely  round  as  may  be  required. 

The  hour  arc  is  read  by  the  lower  edge  of  the  graduated 
side  of  the  declination  arc. 

The  axis  of  the  declination  arc,  or  indeed  the  whole  socket 
p,  is  appropriately  termed  the  polar  axis. 

The  Adjuster . — Besides  the  parts  shown  in  the  cut, 
there  is  also  an  arm  used  in  the  adjustment  of  the  instru- 
ment as  described  hereafter,  but  laid  aside  in  the  box  when 
that  is  effected. 

The  parts  just  described  constitute  properly  the  solar 
apparatus. 

Besides  these,  however,  are  seen  the  needle  box,  n,  with 


THE  SOLAR  COMPASS. 

its  arc  and  tangent-screw;  and  the  spirit  levels,  for  bring- 
ing the  whole  instrument  to  a horizontal- position. 

The  Needle  Box > n , has  an  arc  of  about  36°  in  extent, 
divided  to  half  degrees,  and  figured  from  the  centre  or  zero 
mark  on  either  side. 

The  needle,  which  is  made  as  in  other  instruments,  except 
that  the  arms  are  of  unequal  lengths,  is  raised  or  lowered 
by  a lever  shown  in  the  cut. 

The  needle-box  is  attached  by  a projecting  arm  to  a tan- 
gent-screw,  ty  by  which  it  is  moved  about  its  centre,  and  its 
needle  set  to  any  variation. 

This  variation  is  also  read  off  by  the  vernier  on  the  end  of 
the  projecting  arm,  reading  to  three  minutes  a graduated 
arc,  attached  to  the  plate  of  the  compass. 

The  Bevels  seen  with  the  solar  apparatus,  have  ground 
glass  vials,  and  are  adjustable  at  their  ends  like  those  of  our, 
other  instruments. 

The  edge  of  the  circular  plate  on  which  the  solar  work  is 
placed,  is  divided  and  figured  at  intervals  of  ten  degrees,  and 
numbered,  as  shown,  from  0 to  90  on  each  side  of  the  line 
of  sight. 

These  graduations  are  used  in  connection  with  a little 
brass  pin,  seen  in  the  centre  of  the  plate,  to  obtain  approxi- 
mate bearings  of  lines,  which  are  not  important  enough  to 
require  a close  observation. 

Lines  of  Refraction. — The  inside  faces  of  the  sights 
are  also  graduated  and  figured,  to  indicate  the  amount  of 
refraction  to  be  allowed  when  the  sun  is  near  the  horizon. 
These  are  not  shown  in  the  cut. 

Definition  of  Astronomical  Terms . 

Before  proceeding  to  describe  the  principles  and  adjust- 
ments of  this  instrument,  a brief  statement  of  the  terms 
employed  may  here  be  appropriately  made. 


THE  SOLAR  COMPASS. 


93 


The  Sun  is  the  centre  of  the  solar  system,  remaining 
constantly  fixed  in  its  position,  though,  for  .the  sake  of 
convenience,  often  spoken  of  as  in  motion  around  the 
earth. 

The  Earth  makes  a complete  revolution  around  the 
sun  in  365  days,  6 hours,  very  nearly. 

It  also  rotates  about  an  imaginary  line  passing  through 
its  centre,  and  termed  its  axis , once  in  twenty-four  hours, 
turning  from  west  to  east. 

The  Poles  are  the  extremities  of  the  axis  ; that  in  our 
own  hemisphere,  known  as  the  north  pole,  if  produced  in- 
definitely towards  the  concave  surface  of  the  heavens,  would 
reach  a point  situated  near  the  polar  star,  and  called  the 
north  pole  of  the  heavens. 

The  Equator  is  an  imaginary  line  passing  around  the 
earth  equi-distant  from  the  poles,  and  at  right  angles  with 
them. 

If  the  plane  of  the  equator  is  produced  to  the  heavens,  it 
forms  what  is  termed  the  equator  of  the  heavens. 

The  Orbit  of  the  earth  is  the  path  in  which  it  moves 
in  making  its  yearly  revolution. 

Tf  the  plane  of  this  orbit  were  extended  to  the  heavens, 
it  would  form  the  ecliptic , or  the  sun’s  apparent  path  in 
the  heavens. 

The  earth’s  axis  is  inclined  to  its  orbit  at  an  angle  of 
about  23°  28',  making  the  angle  between  the  earth’s  orbit 
and  its  equator,  or  between  the  celestial  equator  and  the 
ecliptic,  of  the  same  amount. 

The  Equinoxes  are  the  two  points  in  which  the 
ecliptic  and  the  celestial  equator  intersect  each  other. 

The  .Declination  of  the  sun  is  its  angular  distance 
north  or  south  of  the  celestial  equator ; when  the  sun  is  at 
the  equinoxes,  that  is  about  the  21st  of  March  and  the  21st 
of  September  of  each  year,  his  declination  is  0,  or  he  is  said 


94 


THE  SOLAR  COMPASS. 


to  be  on  the  equator  ; from  these  points  his  declination  in- 
creases from  day  to  day,  and  from  hour  to  hour,  until,  on 
the  21st  of.  June  and  21st  of  December,  he  is  23°  28'  dis- 
tant from  the  equator. 

It  is  the  declination  which  causes  the  sun  to  appear  so 
much  higher  in  summer  than  in  winter,  his  altitude  in  the 
heavens  being  in  fact  nearly  47°  more  on  the  21st  of  June 
than  it  is  on  the  21st  of  December. 

The  Horizon  of  a place  is  the  surface  which  is  de- 
fined by  a plane  supposed  to  pass  through  the  place  at  right 
angles  to  a vertical  or  plumb  line,  and  to  bound  our  vision 
at  the  surface  of  the  earth. 

The  horizon  or  a horizontal  surface  is  determined  by  the 
surface  of  any  liquid  when  at  rest,  or  by  the  spirit  levels  of 
an  instrument. 

The  Zenith  of  any  place  is  the  point  directly  over 
head,  at  right  angles  to  the  horizon. 

The  Meridian  of  any  place  is  a great  circle  passing 
through  the  zenith  of  a place,  and  the  poles  of  the  earth. 

The  meridian,  or  true  north  and  south  line  of  any  place, 
is  the  line  determined  by  the  intersection  of  the  plane  of 
the  meridian  circle  with  the  plane  of  the  horizon. 

The  Meridian  Altitude  of  the  sun  is  its  angular 
elevation  above  the  horizon,  when  passing  the  meridian  of  a 
place. 

The  Latitude  of  a place  is  its  distance  north  or  south 
of  the  equator,  measured  on  a meridian.  At  the  equator 
the  latitude  is  0°,  at  the  poles  90°. 

The  Longitude  of  a place  is  its  distance  in  degrees  or 
in  time,  east  or  west  of  a given  place  taken  as  the  starting- 
point  or  first  meridian  ; it  is  measured  on  the  equator  or 
any  parallel  of  latitude. 

In  the  Nautical  Almanac,  which  is  commonly  used  with 
the  Solar  Compass,  the  longitude  of  the  principal  places 


THE  SOLAR  COMPASS. 


95 


in  the  United  States  is  reckoned  from  Greenwich,  England, 
and  expressed  both  in  degrees  and  hours. 

The  Zenith  Distance  of  any  heavenly  body,  is  its 
angular  distance  north  or  south  of  the  zenith  of  a place, 
measured  when  the  body  is  on  the  meridian. 

Suppose  a person  situated  on  the  equator  at  the  time  of 
the  equinoxes,  the  sun,  when  on  the  meridian,  would  be  in 
the  zenith  of  the  place,  and  the  poles  of  the  earth  would, 
of  course,  lie  in  the  plane  of  his  horizon. 

Disregarding  for  the  present  the  declination  of  the  sun, 
let  us  suppose  the  person  travels  towards  the  north  pole. 

As  he  passes  to  the  north,  the  sun  will  descend  from  the 
zenith,  and  the  pole  rise  from  the  horizon  in  the  same  pro- 
portion, until  when  he  arrives  at  the  north  pole  of  the 
earth,  the  sun  will  have  declined  to  the  horizon,  and  the 
pole  of  the  heavens  will  have  reached  the  zenith. 

The  altitude  of  the  pole  at  any  place,  or  the  distance  of 
the  sun  from  the  zenith,  would,  in  the  case  supposed,  give 
the  observer  the  latitude  of  that  place. 

If  we  now  take  into  account  the  sun’s  declination,  it 
would  increase  or  diminish  its  meridian  altitude,  according 
as  it  passes  north  or  south  of  the  equator ; but  the  declina- 
tion of  the  sun  at  any  time  being  known,  its  zenith  dis- 
tance, and  therefore  the  latitude  of  the  place,  can  be 
readily  ascertained  by  an  observation  made  when  it  is  on 
the  meridian. 

As  we  shall  see  hereafter,  it  is  by  this  method  that  we 
obtain  the  latitude  of  any  place  by  the  Solar  Compass. 

Time . — A solar  day  is  the  interval  of  time  between  the 
departure  of  the  sun  from  the  meridian  of  a place,  and  its 
succeeding  return  to  the  same  position. 

The  length  of  the  solar  day,  by  reason  of  the  varying 
velocities  of  the  earth  in  its  orbit,  and  the  inclination  of 
its  axis,  is  continually  changing. 


96 


THE  SOLAR  COMPASS. 


In  order  to  have  a uniform  measure  of  time,  we  have 
recourse  to  what  is  termed  a mean  solar  day , the  length  of 
which  is  equal  to  the  mean  or  average  of  all  the  solar  days 
in  a year. 

The  time  thus  given  is  termed  mean  time , and  is  that  to 
which  clocks  and  watches  are  adjusted  for  the  ordinary 
business  of  life. 

The  sun  is  sometimes  faster,  and  sometimes  slower  than 
the  clock,  the  difference  being  termed  the  equation  of  time . 

The  moment  when  the  sun  is  on  the  meridian  of  any 
place  is  termed  apparent  noon , and  this  being  ascertained, 
we  can,  by  referring  to  the  equation  of  time  for  the  given 
day,  and  adding  to,  or  subtracting  from,  apparent  noon, 
according  as  the  sun  is  slow  or  fast,  obtain  the  time  of 
mean  noon , by  which  to  set  the  watch  or  chronometer. 

Difference  of  Longitude. — As  the  earth  makes  a 
complete  rotation  upon  its  axis  once  a day,  every  point  on 
its  surface  must  pass  over  360°  in  24  hours,  or  15°  in  one 
hour,  and  so  on  in  the  same  proportion. 

And  as  the  rotation  is  from  west  to  east,  the  sun  would 
come  to  the  meridian  of  every  place  15°  west  of  Greenwich, 
just  one  hour  later  than  the  time  given  in  the  Almanac  for 
apparent  noon  at  that  place. 

To  an  observer  situated  at  Troy,  N.Y.,  the  longitude  of 
which  is  in  time  4 hours  54  minutes  40  seconds,  the  sun 
would  come  to  the  meridian  nearly  five  hours  later  than  at 
Greenwich,  and  thus  when  it  was  12  M.  at  that  place,  it 
would  be  but  about  7 o’clock  A.  M.  in  Troy. 

JRe fraction. — By  reason  of  the  increasing  density  of 
the  atmosphere  from  its  upper  regions  to  the  earth’s  sur- 
face, the  rays  of  light  from  the  sun  are  bent  out  of  their 
course,  so  as  to  make  his  altitude  appear  greater  than  is 
actually  the  case. 

The  amount  of  refraction  varies,  according  to  the  alti- 


THE  SOLAR  COMPASS. 


91 


tude  of  the  body  observed  ; being  0 when  it  is  in  the  zenith, 
about  one  minute  when  midway  from  the  horizon  to  the 
zenith,  and  almost  3T  when  in  the  horizon. 

Effect  of  Incidental  Refraction.— It  will  be  seen 
by  referring  to  the  instrument,  that  the  effect  of  the  ordi- 
nary refraction  upon  the  position  of  the  sun’s  image  with 
reference  to  the  equatorial  lines,  which,  in  fact,  are  the 
only  ones  to  be  regarded  in  running  lines  with  the  Solar 
Compass,  is  continually  changing,  not  only  with  the  change 
of  latitude,  but  also  with  that  of  the  sun’s  declination  from 
hour  to  hour,  and  the  motion  of  the  revolving  arm  as  it  fol- 
lows the  sun  in  its  daily  revolution. 

If  the  equatorial  lines  were  always  in  the  same  vertical 
plane  with  the  sun,  as  would  be  the  case  at  the  equator  at 
the  time  of  the  equinoxes,  it  is  evident  that  refraction 
would  have  no  effect  upon  the  position  of  the  image  between 
these  lines,  and  therefore  would  not  be  of  any  importance 
to  the  surveyor. 

But  as  we  proceed  further  north,  and  as  the  sun’s  decli- 
nation to  the  south  increases,  the  refraction  also  increases, 
and  must  now  be  taken  into  account. 

Again,  the  angle  which  the  equatorial  lines  make  with  the 
horizon  is  continually  changing  as  the  arm  is  made  to  fol- 
low the  motion  of  the  sun  during  the  course  of  a day. 

Thus,  in  the  morning  and  evening  they  are  more  or  less 
inclined  to  the  horizon,  while  at  noon  they  are  exactly 
parallel  to  it. 

And  thus  it  follows  that  the  excess  of  refraction  at  morn- 
ing and  evening  is  in  some  measure  balanced  by  the  fact 
that  the  position  of  the  sun’s  image  with  reference  to  the 
equatorial  lines  is  then  less  affected  by  it,  on  account  of  the 
greater  inclination  of  the  lines  to  the  horizon. 

Allowance  for  Refraction. — The  proper  allow- 
ance to  be  made  for  refraction  in  setting  off  the  declination 


98 


THE  SOLAR  COMPASS. 


of  the  sun  upon  the  Solar  Compass  has  long  been  a source 
of  perplexity  to  the  surveyor ; we  have,  accordingly,  given 
the  subject  a good  deal  of  attention,  and  now  publish  a 
table  to  be  found  at  the  end  of  this  article,  by  which  the 
amount  of  refraction  for  any  hour  of  any  day  of  the  year 
can  be  ascertained,  and  set  off  with  a degree  of  accuracy 
which  is  all  that  can  be  desired. 

The  use  of  this  table  will  be  fully  described  when  we 
come  to  speak  of  the  manner  of  setting  off  the  declination 
in  the  actual  use  of  the  instrument. 

Principles  of  the  Solar  Compass. 

The  interval  between  two  equatorial  lines  c c,  in  Pig.  26, 
as  well  as  between  the  hour  lines  bb,  is  just  sufficient  to 
include  the  circular  image  of  the  sun  as  formed  by  the  solar 
lens  on  the  opposite  end  of  the  revolving  arm  h , Pig.  25. 

When,  therefore,  the  instrument  is  made  perfectly  hori- 
zontal, the  equatorial  lines  and  the  opposite  lenses  being 
accurately  adjusted  to  each  other  by  a previous  operation, 
and  the  sun’s  image  brought  within  the  equatorial  lines,  his 
position  in  the  heavens,  with  reference  to  the  horizon,  will 
be  defined  with  precision. 

Suppose  the  observation  to  be  made  at  the  time  of  one  of 
the  equinoxes;  the  arm  h , set  at  zero  on  the  declination  arc 
b,  and  the  polar  axis  p,  placed  exactly  parallel  to  the  axis  of 
the  earth. 

Then  the  motion  of  the  arm  h , if  revolved  on  the  spindle 
of  the  declination  arc  around  the  hour  circle  c,  will  exactly 
correspond  with  the  motion  of  the  sun  in  the  heavens,  on  the 
given  day  and  at  the  place  of  observation  ; so  that  if  the 
sun’s  image  was  brought  between  the  lines  c c,  in  the  morn- 
ing, it  would  continue  in  the  same  position,  passing  neither 
above  nor  below  the  lines,  as  the  arm  was  made  to  revolve 
in  imitation  of  the  motion  of  the  sun  about  the  earth. 


THE  SOLAR  COMPASS. 


99 


In  the  morning  as  the  snn  rises  from  the  horizon,  the  arm 
h will  be  in  a position  nearly  at  right  angles  to  that  shown 
in  the  cut,  the  lens  being  turned  towards  the  sun,  and  the 
silver  plate  on  which  his  image  is  thrown  directly  opposite. 

As  the  sun  ascends,  the  arm  must  be  moved  around,  until 
when  he  has  reached  the  meridian,  the  graduated  side  of  the 
declination  arc  will  indicate  12  on  the  hour  circle,  and  the 
arm  h , the  declination  arc  b,  and  the  latitude  arc  a , will  be 
in  the  same  plane. 

As  the  sun  declines  from  the  meridian  the  arm  h must  be 
moved  in  the  same  direction,  until  at  sunset  its  position  will 
be  the  exact  reverse  of  that  it  occupied  in  the  morning. 

Allowance  for  Declination . — Let  us  now  suppose 
the  observation  made  when  the  sun  has  passed  the  equinoc- 
tial point,  and  when  his  position  is  affected  by  declination. 

By  referring  to  the  Almanac,  and  setting  off  on  the  arc 
his  declination  for  the  given  day  and  hour,  we  are  still  able 
to  determine  his  position  with  the  same  certainty  as  if  he 
remained  on  the  equator. 

When  the  sun’s  declination  is  south,  that  is,  from  the  22d 
of  September  to  the  20th  of  March  in  each  year,  the  arc  b is 
turned  towards  the  plates  of  the  compass,  as  shown  in  the 
engraving,  and  the  solar  lens,  o,  with  the  silver  plate  oppo- 
site, are  made  use  of  in  the  surveys. 

The  remainder  of  the  year,  the  arc  is  turned  from  the 
plates,  and  the  other  lens  and  plate  employed. 

When  the  Solar  Compass  is  accurately  adjusted,  and  its 
plates  made  perfectly  horizontal,  the  latitude  of  the  place, 
and  the  declination  of  the  sun  for  the  given  day  and  hour, 
being  also  set  off  on  the  respective  arcs,  the  image  of  the 
sun  cannot  be  brought  between  the  equatorial  lines  until  the 
polar  axis  is  placed  in  the  plane  of  the  meridian  of  the  place , 
or  in  a position  parallel  to  the  axis  of  the  earth.  The 
slightest  deviation  from  this  position  will  cause  the  image 


100 


THE  SOLAR  COMPASS. 


to  pass  above  or  below  the  lines,  and  thus  discover  the 
error. 

We  thus,  from  the  position  of  the  sun  in  the  solar  system, 
obtain  a certain  direction  absolutely  unchangeable,  from 
which  to  run  our  lines,  and  measure  the.  horizontal  angles 
required. 

This  simple  principle  is  not  only  the  basis  of  the  construc- 
tion of  the  Solar  Compass,  but  the  sole  cause  of  its  supe- 
riority to  the  ordinary  or  magnetic  instrument.  For  in  a 
needle  instrument,  the  accuracy  of  the  horizontal  angles 
indicated,  and  therefore  of  all  the  observations  made,  depends 
upon  “the  delicacy  of  tfie  needle,  and  the  constancy  with 
which  it  assumes  a certain  direction,  termed  the  magnetic 
meridian.” 

The  principal  causes  of  error  in  the  needle  briefly  stated, 
are  the  dulling  of  the  pivot,  the  loss  of  polarity  in  the 
needle,  the  influence  of  local  attraction,  and  the  effect  of  the 
sun’s  rays,  producing  the  diurnal  variation. 

From  all  these  imperfections  the  solar  instrument  is  free. 

The  sights  and  the  graduated  limb  being  adjusted  to  the 
solar  apparatus,  and  the  latitude  of  the  place  and  the 
declination  of  the  sun  also  set  off  upon  the  respective  arcs, 
we  are  able,  not  only  to  run  the  true  meridian,  or  a due  east 
and  west  course,  but  also  to  set  off  the  horizontal  angles 
with  minuteness  and  accuracy  from  a direction  which  never 
changes,  and  is  unaffected  by  attraction  of  any  kind. 

To  Adjust  the  Solar  Compass . 

The  adjustments  of  this  instrument,  with  which  the  sur- 
veyor will  have  to  do,  are  simple  and  few  in  number,  and 
will  now  be  given  in  order. 

1st.  To  Adjust  the  Levels . — Proceed  precisely  as 
directed  in  the  account  of  the  other  instruments  we  have 
described,  by  bringing  the  bubbles  into  the  centre  of  the 


THE  SOLAR  COMPASS. 


101 


tubes  by  the  leveling  screws  of  the  tripod,  and  then  reversing 
the  instrument  upon  its  spindle,  and  raising  or  lowering  the 
ends  of  the  tubes,  until  the  bubbles  will  remain  in  the  cen- 
tre during  a complete  revolution  of  the  instrument. 

2d.  To  Adjust  the  Equatorial  Lines  and 
Solar  Lenses . — First  detach  the  arm  h from  the  declina- 
tion arc  by  withdrawing  the  screws  shown  in  the  cut  from 
the  ends  of  the  posts  of  the  tangent-screw  k,  and  also  the 
clamp-screw,  and  the  conical  pivot  with  its  small  screws  by 
which  the  arm  and  declination  arc  are  connected. 

The  arm  Ti , being  thus  removed,  attach  the  adjuster  in  its 
place  by  replacing  the  conical  pivot  and  screws,  and  insert 
the  clamp-screw  so  as  to  clamp  the  adjuster  at  any  point  on 
the  declination  arc. 

Now  level  the  instrument,  place  the  arm  h on  the  adjuster, 
with  the  same  side  resting  against  the  surface  of  the  decli- 
nation arc  as  before  it  was  detached.  Turn  the  instrument 
on  its  spindle  so  as  to  bring  the  solar  lens  to  be  adjusted  in 
the  direction  of  the  sun,  and  raise  or  lower  the  adjuster  on 
the  declination  arc,  until  it  can  be  clamped  in  such  a posi- 
tion as  to  bring  the  sun’s  image  as  near  as  may  be  between 
the  equatorial  lines  on  the  opposite  silver  plate,  and  bring 
the  image  precisely  into  position  by  the  tangent  of  the  lati- 
tude arc  or  the  leveling-screws  of  the  tripod.  Then  care- 
fully turn  the  arm  half  way  over,  until  it  rests  upon  the 
adjuster  by  the  opposite  faces  of  the  rectangular  blocks,  and 
again  observe  the  position  of  the  sun’s  image. 

If  it  remains  between  the  lines  as  before,  the  lens  and 
plate  are  in  adjustment ; if  not,  loosen  the  three  screws 
which  confine  the  plate  to  the  block,  and  move  the  plate 
under  their  heads,  until  one  half  the  error  in  the  position  of 
the  sun’s  image  is  removed. 

Again  bring  the  image  between  the  lines,  and  repeat  the 
operation  until  it  will  remain  in  the  same  situation,  in  both 


102 


THE  SOLAR  COMPASS. 


positions  of  the  arm,  when  the  adjustment  will  be  com- 
pleted. 

To  adjust  the  other  lens  and  plate,  reverse  the  arm  end 
for  end  on  the  adjuster,  and  proceed  precisely  as  in  the 
former  case,  until  the  same  result  is  attained. 

In  tightening  the  screws  over  the  silver  plate,  care  must 
be  taken  not  to  move  the  plate. 

This  adjustment  now  being  complete,  the  adjuster  should 
be  removed,  and  the  arm  h , with  its  attachments,  replaced 
as  before. 

3d.  To  Adjust  the  Vernier  of  the  Declination 
Arc . — Having  leveled  the  instrument,  and  turned  its  lens 
in  the  direction  of  the  sun,  clamp  to  the  spindle,  and  set 
the  vernier  v,  of  the  declination  arc,  at  zero,  by  means  of 
the  tangent-screw  at  k,  and  clamp  to  the  arc. 

See  that  the  spindle  moves  easily  and  yet  truly  in  the 
socket,  or  polar  axis,  and  raise  or  lower  the  latitude  arc 
by  turning  the  tangent-screw  /,  until  the  sun’s  image  is 
brought  between  the  equatorial  lines  on  one  of  the  plates. 
Clamp  the  latitude  arc  by  the  screw,  and  bring  the  image 
precisely  into  position  by  the  leveling-screws  of  the  tripod 
or  socket,  and  without  disturbing  the  instrument,  carefully 
revolve  the  arm  h,  until  the  opposite  lens  and  plate  are 
brought  in  the  direction  of  the  sun,  and  note  if  the  sun’s 
image  comes  between  the  lines  as  before. 

If  it  does,  there  is  no  index  error  of  the  declination  arc  ; 
if  not,  with  the  tangent-screw  k,  move  the  arm  until  the 
sun’s  image  passes  over  half  the  error ; again  bring  the 
image  between  the  lines,  and  repeat  the  operation  as  before, 
until  the  image  will  occupy  the  same  position  on  both  the 
plates. 

We  shall  now  find,  however,  that  the  zero  marks  on  the 
arc  and  the  vernier  do  not  correspond,  and  to  remedy  this 
error,  the  little  flat-head  screws  above  the  vernier  must  be 


THE  SOLAR  COMPASS. 


103 


loosened  until  it  can  be  moved  so  as  to  make  the  zeros 
coincide,  when  the  operation  will  be  completed. 

4th.  To  Adjust  the  Solar  Apparatus  to  the 
Compass  Sights. — First  level  the  instrument,  and  with 
the  clamp  and  tangent-screws  set  the  main  plate  at  90°  by 
the  verniers  and  horizontal  limb.  Then  remove  the  clamp- 
screw,  and  raise  the  latitude  arc  until  the  polar  axis  is  by 
estimation  very  nearly  horizontal,  and  if  necessary,  tighten 
the  screws  on  the  pivots  of  the  arc,  so  as  to  retain  it  in  this 
position. 

Fix  the  vernier  of  the  declination  arc  at  zero,  and  direct 
the  equatorial  sights  to  some  distant  and  well  marked 
object,  and  observe  the  same  through  the  compass  sights. 
If  the  same  object  is  seen  through  both,  and  the  verniers 
read  to  90°  on  the  limb,  the  adjustment  is  complete  ; if  not, 
the  correction  must  be  made  by  moving  the  sights  or  chang- 
ing the  position  of  the  verniers. 

It  should  be  remarked  that  as  the  solar  work  is  attached 
permanently  to  the  sockets,  and  this  adjustment  is  made  by 
the  maker,  it  will  need  no  further  attention  at  the  hands  of 
the  surveyor  except  in  case  of  serious  accidents. 

The  other  adjustments  are  of  course  also  made  in  the 
process  of  finishing  the  instrument,  and  are  liable  to  very 
little  derangement  in  the  ordinary  use  of  the  Solar  Com- 
pass. 

Tripod , &c,,  for  Solar  Compass . 

This  instrument  should  always  be  used  on  a tripod,  with 
screws  for  ready  and  accurate  leveling,  and  a tangent-screw 
for  directing  it  to  any  given  point. 

For  this  purpose  a leveling-head  with  tangent-screw,  &c., 
similar  to  those  shown  in  the  cuts  of  the  Surveyors5  Transit 
is  furnished,  unless  otherwise  ordered,  with  every  instru- 
ment, 


104 


THE  SOLAR  COMPASS. 


Leveling  Adopter. — For  more  rapid  leveling  of  the 
Solar  Compass  as  well  as  other  instru- 
ments hereafter  described,  we  have 
recently  devised  the  arrangement  shown 
at  a,  Fig.  27,  which  is  screwed  into  the 
top  of  the  tripod  like  the  ordinary  lev- 
eling head. 

This  can  be  used  either  with  a simple 
ball-spindle,  or  with  the  compound  ball 
with  tangent  screw  as  shown  in  the  cut. 

The  instrument  is  leveled  very  nearly 
upon  the  ball,  and  finally  made  truly 
horizontal  by  the  leveling  screws. 

It  also  revolves  upon  the  spindle  as 
upon  the  ordinary  compass-ball,  but 
can  be  clamped  at  pleasure  to  the  spin- 
dle, and  then  by  the  tangent-screw  di- 
rected precisely  to  any  object. 

A simple  ball  with  extra  cap  is  also 
supplied,  which  can  be  substituted  for  the  compound  ball, 
by  unscrewing  the  cap  which  confines  it,  as  shown  in  the 
figure.— The  price  of  the  leveling  adopter,  without  tripod 
or  ball  spindle,  is  $7.00;  with  tripod  and  compound  tangent 
ball,  as  shown  in  Fig.  27,  $18.00. 

To  Use  the  Solar  Compass . 

Before  this  instrument  can  be  used  at  any  given  place,  it 
is  necessary  to  set  off  upon  its  arcs  both  the  decimation  of 
the  sun  as  affected  by  its  refraction  for  the  given  day  and  hour, 
and  the  latitude  of  the  place  where  the  observation  is  made. 

To  Set  off  the  Declination . — The  declination  of 
the  sun,  given  in  the  ephemeris  of  the  Nautical  Almanac 
from  year  to  year,  is  calculated  for  apparent  noon  at  Green- 
wich, England. 

To  determine  it  for  any  other  hour  at  a place  m the  U.  S., 


Fig.  27. 


THE  SOLAR  COMPASS. 


105 


reference  must  be  had,  not  only  to  the  difference  of  time 
arising  from  the  longitude,  but  also  to  the  change  of  decli- 
nation from  day  to  day. 

The  longitude  of  the  place,  and  therefore  its  difference  in 
time,  if  not  given  directly  in  the  tables  of  the  Almanac,  can 
be  ascertained  very  nearly  by  reference  to  that  of  other 
places  given,  which  are  situated  on,  or  very  nearly  on,  the 
same  meridian. 

It  is  the  practice  of  surveyors  in  the  states  east  of  the 
Mississippi  to  allow  a difference  of  six  hours  for  the  differ- 
ence in  longitude,  calling  the  declination  given  in  the 
Almanac  for  12  M.,  that  of  6 A.  M.,  at  the  place  of  obser- 
vation. 

Beyond  the  meridian  of  Santa  Fe,  the  allowance  would 
be  about  seven  hours,  and  in  California,  Oregon,  and  Wash- 
ington Territory  about  eight  hours. 

Having  thus  the  difference  of  time,  we  very  readily  ob- 
tain the  declination  for  a certain  hour  in  the  morning, 
which  would  be  earlier  or  later  as  the  longitude  was  greater 
or  less,  and  the  same  as  that  of  apparent  noon  at  Green- 
wich on  the  given  day.  Thus,  suppose  the  observation 
made  at  a place,  say,  five  hours  later  than  Greenwich,  then 
the  declination  given  in  the  Almanac  for  the  given  day  at 
noon,  affected  by  the  refraction,  would  be  the  declination  at 
the  place  of  observation  for  7 o’clock,  A.  M. ; this  gives  us 
the  starting-point. 

To  obtain  the  declination  for  the  other  hours  of  the  day, 
take  from  the  Almanac  the  declination  for  apparent  noon  of 
the  given  day,  and,  as  the  declination  is  increasing  or  de- 
creasing, add  to  or  subtract  from  the  declination  of  the  first 
hour  the  difference  for  one  hour  as  given  in  the  ephemeris, 
which  will  give,  when  affected  by  the  refraction,  the  decli- 
nation for  the  succeeding  hour  ; and  proceed  thus  in  mak- 
ing a table  of  the  declination  for  every  hour  of  the  day. 


106 


THE  SOLAR  COMPASS. 


Explanation  of  the  Table  of  Refractions . 

The  table  is  calculated  for  latitudes  between  30°  and  50° 
at  intervals  of  2-|°,  that  being  as  near  as  is  required. 

The  declination  ranges  from  0 to  20°  both  north  and 
south,  the  4-  declinations  being  north,  and  — south,  and  is 
given  for  every  five  degrees,  that  being  sufficiently  near  for 
all  practical  purposes. 

The  hour  angle  in  the  first  column  indicates  the  distance 
of  the  sun  from  the  meridian  in  hours,  the  refraction  given 
for  0 hours  being  that  which  affects  the  observed  declina- 
tion of  the  sun  when  on  the  meridian,  commonly  known  as 
meridional  refraction  ; the  refraction  for  the  hours  just  be- 
fore and  after  noon  is  so  nearly  that  of  the  meridian,  that  it 
may  be  called  and  allowed  as  the  same. 

When  the  table  is  used,  it  must  be  borne  in  mind  that 
when  the  declination  is  north  or  + in  the  table,  the  refrac- 
tion is  to  be  added ; when  the  declination  is  south  or  — , 
the  refraction  must  be  subtracted. 

It  will  be  noticed  that  the  refraction  in  south  or  — 
declination  increases  very  rapidly  as  the  sun  nears  the  hori- 
zon, showing  that  observations  should  not  be  taken  with 
the  sun  when  south  of  the  equator,  less  than  one  hour  from 
the  horizon. 

Thus,  suppose  it  was  required  to  obtain  the  declination 
for  the  different  hours  of  April  16,  1883,  at  Troy,  N.  Y. 

The  longitude  in  time  is  4 hours  54  minutes  40  seconds, 
or  practically  5 hours  ; so  that  the  declination  given  in 
the  ephemeris  for  apparent  noon  of  that  day  at  Greenwich 
would  be  that  of  7 A.  M.  at  Troy. 

To  obtain  the  declination  of  the  given  day  proceed  as 
follows : 


THE  SOLAR  COMPASS. 


107 


Declination  at  Greenwich  at  noon  of  April  16,  1883, 

N.  10°  6'  2"  + 

N.  10°  6'  2"  + Refr.  5 brs.  1'  58"=10°  8'  0"=Dec.  at  7 A. M.  Troy 
add  hr.  dif.  53" 


N.  10°  6' 56"  + 
add  hr.  dif.  53" 

« 4 « 

I'll" =10°  8'  0".6= 

“ 8 

u 

N.  10°  7' 48"  + 
add  hr.  dif.  53" 

“ 3 “ 

0'  52" =10°  8' 40"  = 

“ 9 

N.  10°  8' 41"  + 
add  hr.  dif.  53" 

“ 2 “ 

0'  39" =10°  9' 20"  = 

“ 10 

a 

N.  10°  9' 34"  + 
add  hr.  dif.  53" 

“ 1 “ 

0'36"=10°10'10"  = 

“ 11 

N.  10°  10'  27"  + 
add  hr.  dif.  53" 

“ 0 “ 

0'36"=10oll'03"  = 

“ 12 

M. 

N.  10° 11' 20"  + 
add  hr.  dif.  53" 

“ 1 “ 

0'86"=10°11'56"  = 

“ 1 

P.  M. 

N.  10°  12'  13"  + 
add  hr.  dif.  53" 

“ 2 “ 

0'39"=10°12'52"  = 

“ 2 

u 

N.  10°  13'  06"  + 
add  hr.  dif.  53" 

“ 3 “ 

O'  52" =10°  13'  58"  = 

“ 3 

a 

N.  10°  13'  59"  + 
add  hr.  dif.  53" 

“ 4 “ 

V 11" =10°  15'  10"  = 

“ 4 

n 

N. 10° 14  49" + 

“ 5 “ 

1'58"=10°16'50"  = 

“ 5 

u 

Again,  suppose  it  was  desired  to  obtain  the  corrected 
declination  for  the  different  hours  of  Oct.  16,  1883,  at 
Troy,  N.  Y. 

The  difference  in  time  being  nearly  5 hours,  and  the 
declination  at  Greenwich,  noon,  S.  8°  51'  47". 7,  that  decli- 
nation affected  by  the  refraction  would  give  the  true  decli- 
nation for  7 A.  M.  at  Troy  ; the  latitude  being  nearly  42°  30'. 
The  declination  being  now  south,  the  refraction  is  to  be 
subtracted,  but  the  hourly  difference. is  to  be  added  because 
the  declination  is  increasing,  as  in  the  first  example : thus, 


108 


THE  SOLAR  COMPASS. 


S.  8°  51'  47". 7— Ref r.  5 hrs.9'  24"=8°  42'  23"=Dec.  at  7 a.m.  at  Troy 


add  hr.  dif.55" 

S.  8°  52'  42"  - 
add  hr.  dif.55" 

“ 4 “ 

2'  49"  =8°  49'  53"  = 

tt 

8 

tt 

S.  8°  53' 37"  - 
add  hr.  dif.55" 

“ 3 ‘‘ 

1'  49"  =8°  51' 48"  = 

(( 

9 

M 

S.  8°  54' 32"  - 
add  hr.  dif.55" 

“ 2 <• 

V 26" =8°  53' 06"= 

“ 

10 

tt 

S.  8°  55' 27"  - 
add  hr.  dif.55" 

“ 1 “ 

T 14"  =8°  54'  13"  = 

U 

11 

“ 

S.  8°  56' 22"  - 
add  hr  dif.55" 

“ 0 “ 

V 14"  =8°  55' 08"  = 

u 

12 

M. 

S.  8°  57' 17"  - 
add  hr.  dif.55" 

“ 1 “ 

V 14"  =8°  56'  03"= 

a 

1 

P.M. 

S.  8°  58'  12"  - 
add  hr.  dif.55" 

“ 2 “ 

1'  26"  =8°  56'  46"= 

t( 

2 

tt 

S.  8°  59' 07"  - 
add  hr.  dif.55" 

“ 3 “ 

V 49"  =8°  57'  18"= 

tt 

3 

a 

S.  9°  00' 02"  - 
add  hr.  dif.55" 

“ 4 “ 

2'  49" =8°  57'  13"= 

it 

4 

tt 

S.  9°  00' 57"  - 

“ 5 “ 

9'  24" =8°  51'  33"= 

tt 

5 

tt 

We  believe  it  will  be  found  that  the  use  of  the  table  as 
illustrated  above,  will  not  only  relieve  the  surveyor  of  the 
perplexity  hitherto  attending  the  subject  of  refractions,  but 
will  also  enable  him  to  secure  more  accurate  results  than 
were  possible  by  the  methods  usually  given. 

The  calculation  of  the  declination  for  the  different  hours 
of  the  day,  should  of  course  be  made  and  noted  before  the 
surveyor  commences  his  work,  that  he  may  lay  off  the 
change  from  hour  to  hour,  from  a table  prepared  as  above 
described. 

To  Set  Off  the  Latitude. — Find  the  declination  of 
the  sun  for  the  given  day  at  noon,  at  the  place  of  observa- 
tion as  just  described,  and  with  the  tangent-screw  set  it  off 
5 


THE  SOLAR  COMPASS. 


109 


upon  the  declination  arc,  and  clamp  the  arm  firmly  to  the 
arc. 

Observe  in  the  Almanac  the  equation  of  time  for  the  given 
day,  in  order  to  know  about  the  time  the  sun  will  reach  the 
meridian. 

Then,  about  fifteen  or  twenty  minutes  before  this  time, 
set  up  the  instrument,  level  it  carefully,  fix  the  divided  sur- 
face of  the  declination  arc  at  12  on  the  hour  circle,  and  turn 
the  instrument  upon  its  spindle  until  the  solar  lens  is 
brought  into  the  direction  of  the  sun. 

Loosen  the  clamp-screw  of  the  latitude  arc,  and  with  the 
tangent-screw  raise  or  lower  this  arc  until  the  image  of  the 
sun  is  brought  precisely  between  the  equatorial  lines,  and 
turn  the  instrument  from  time  to  time  so  as  to  keep  the 
image  also  between  the  hour  lines  on  the  plate. 

As  the  sun  ascends,  its  image  will  move  below  the  lines, 
and  the  arc  must  be  moved  to  follow  it.  Continue  thus, 
keeping  it  between  the  two  sets  of  lines  until  its  image 
begins  to  pass  above  the  equatorial  lines,  which  is  also  the 
moment  of  its  passing  the  meridian. 

Now  read  off  the  vernier  of  the  arc,  and  we  have  the  lati- 
tude of  the  place,  which  is  always  to  be  set  off  on  the  arc 
when  the  compass  is  used  at  the  given  place. 

It  is  the  practice  of  surveyors  using  the  Solar  Compass  to 
set  off,  in  the  manner  just  described,  the  latitude  of  the  point 
where  the  survey  begins,  and  to  repeat  the  observation  and 
correction  of  the  latitude  arc  every  day  when  the  weather  is 
favorable,  there  being  also  nearly  an  hour  at  mid-day  when 
the  sun  is  so  near  the  meridian  as  not  to  give  the  direction 
of  lines  with  the  certainty  required. 

To  Run  Lines  with  the  Solar  Compass . — Hav- 
ing set  off  in  the  manner  just  given  the  latitude  and  declina- 
tion upon  their  respective  arcs,  the  instrument  being  also 
in  adjustment,  the  surveyor  is  ready  to  run  lines  by  the  sun, 


110 


THE  SOLAR  COMPASS. 


To  do  this,  the  instrument  is  set  over  the  station  and 
carefully  leveled,  the  plates  clamped  at  zero  on  the  horizontal 
limb,  and  the  sights  directed  north  and  south,  the  direction 
being  given,  when  unknown,  approximately  by  the  needle. 

The  solar  lens  is  then  turned  to  the  sun,  and  with  one  hand 
on  the  instrument,  and  the  other  on  the  revolving  arm,  both 
are  moved  from  side  to  side,  until  the  sun’s  image  is  made 
to  appear  on  the  silver  plate;  when  by  carefully  continuing 
the  operation,  it  may  be  brought  precisely  between  the 
equatorial  lines. 

Allowance  being  now  made  for  refraction,  the  line  of  sights 
will  indicate  the  true  meridian  ; the  observation  may  now  be 
made,  and  the  flag-man  put  in  position. 

When  a due  east  and  west  line  is  to  be  run,  the  verniers 
of  the  horizontal  limb  are  set  at  90°,  and  the  sun’s  image 
kept  between  the  lines  as  before. 

The  Solar  Compass  being  so  constructed  that  when  the 
sun’s  image  is  in  position  the  limb  must  be  clamped  at  0 in 
order  to  run  a true  meridian  line,  it  will  be  evident  that  the 
bearing  of  any  line  from  the  meridian,  may  be  read  by  the 
verniers  of  the  limb  precisely  as  in  the  ordinary  magnetic 
compass,  the  bearing  of  lines  are  read  from  the  ends  of  the 
needle. 

Use  of  the  Needle . — In  running  lines,  the  magnetic 
needle  is  always  kept  with  the  sun ; that  is,  the  point  of 
the  needle  is  made  to  indicate  0 on  the  arc  of  the  compass 
box,  by  turning  the  tangent-screw  connected  with  its  arm 
on  the  opposite  side  of  the  plate.  By  this  means  the  lines 
can  be  run  by  the  needle  alone  in  case  of  the  temporary 
disappearance  of  the  sun;  but,  of  course,  in  such  cases  the 
surveyor  must  be  sure  that  no  local  attraction  is  exerted. 

The  variation  of  the  needle,  which  is  noted  at  every  station, 
is  read  off  in  degrees  and  minutes  on  the  arc,  by  the  edge  of 
which  the  vernier  of  the  needle-box  moves. 


THE  SOLAR  COMPASS. 


Ill 


Allowance  for  the  Earth’s  Curvature . — When 
long  lines  are  run  by  the  Solar  Compass,  either  by  the  true 
meridian,  or  due  east  and  west,  allowance  must  be  made  for 
the  curvature  of  the  earth. 

Thus,  in*  running  north  or  south,  the  latitude  changes 
about  one  minute  for  every  distance  of  92  chains  30  links, 
and  the  side  of  a township  requires  a change  on  the  latitude 
arc  of  5'  12",  the  township,  of  course,  being  six  miles  square. 

This  allowance  is  of  constant  use  where  the  surveyor  fails 
to  get  an  observation  on  the  sun  at  noon,  and  is  a very  close 
approximation  to  the  truth. 

In  running  due  east  and  west,  as  in  tracing  the  standard 
parallels  of  latitude,  the  sights  are  set  at  90°  on  the  limb, 
and  the  line  is  run  at  right  angles  to  the  meridian. 

If  no  allowance  were  made  for  the  earth’s  curvature,  these 
lines  would,  if  sufficiently  produced,  reach  the  equator,  to 
■which  they  are  constantly  tending. 

Of  course,  in  running  short  lines  either  east  or  west,  the 
variation  from  the  parallel  would  be  so  small  as  to  be  of  no 
practical  importance;  but  when  long  sights  are  taken,  the 
correction  should  be  made  by  taking  fore  and  back  sights  at 
every  station,  noticing  the  error  on  the  back  sight,  and  set- 
ting off  one  half  of  it  on  the  fore  sight  on  the  side  towards 
the  pole. 

Time  of  T>ay  by  the  Sun . — The  time  of  day  is  best 
ascertained  by  the  Solar  Compass  when  the  sun  is  on  the 
meridian,  as  at  the  time  of  making  the  observation  for 
latitude. 

The  time  thus  given  is  that  of  apparent  noon,  and  can  be 
reduced  to  mean  time,  by  merely  applying  the  equation  of 
time  as  directed  in  the  Almanac,  and  adding  or  subtracting 
as  the  sun  is  slow  or  fast. 

The  time,  of  course,  can  also  be  taken  before  or  after  noon, 
by  bringing  the  sun’s  image  between  the  hour  lines,  and 


112 


THE  SOLAR  COMPASS. 


noticing  the  position  of  the  divided  edge  of  the  revolving 
arm,  with  reference  to  the  graduations  of  the  hour  circle, 
allowing  four  minutes  of  time  for  each  degree  of  the  arc,  and 
thus  obtaining  apparent  time,  which  must  be  corrected  by 
the  equation  of  time  as  just  described. 

Caution  as  to  the  False  Image. — In  using  the 
compass  upon  the  sun,  if  the  revolving  arm  be  turned  a 
little  one  side  of  its  proper  position,  a false  or  reflected 
image  of  the  sun  will  appear  on  the  silver  plate  in  nearly 
the  same  place  as  that  occupied  by  the  true  one.  It  is 
caused  by  the  reflection  of  the  true  image  from  the  surface 
of  the  arm,  and  is  a fruitful  source  of  error  to  the  inex- 
perienced surveyor.  It  can,  however,  be  readly  distinguished 
from  the  real  image  by  being  much  less  bright,  and  not  so 
clearly  defined. 

Approximate  Bearings. — When  the  bearings  of 
lines,  such  as  the  course  of  a stream,  or  the  boundaries  of  a 
forest,  are  not  desired  with  the  certainty  given  by  the 
verniers  and  horizontal  limb,  a rough  approximation  of  the 
angle  they  make  with  the  true  meridian,  is  obtained  by  the 
divisions  on  the  outside  of  the  circular  plate. 

In  this  operation,  a pencil,  or  thin  straight  edge  of  any 
sort,  is  held  perpendicularly  against  the  circular  edge  of  the 
plate,  and  moved  around  until  it  is  in  range  with  the  eye, 
the  brass  centre-pin,  and  the  object  observed. 

The  bearing  of  the  line  is  then  read  off  at  the  point  where 
the  pencil  is  placed. 

Time  for  Using  the  Solar  Compass. 

The  Solar  Compass,  like  the  ordinary  instrument,  can  be 
used  at  all  seasons  of  the  year,  the  most  favorable  time 
being,  of  couse,  in  the  summer,  when  the  declination  is 
north,  and  the  days  are  long,  and  more  generally  fair. 

It  is  best  not  to  take  the  sun  at  morning  and  evening, 


THE  SOLAR  COMPASS. 


113 


when  it  is  within  half-an-hour  of  the  horizon,  nor  at  noon, 
as  we  have  before  stated,  for  about  the  same  interval,  before 
and  after  it  passes  the  meridian. 


THE  TELESCOPIC  SIGHT. 


Fig.  28. 


Telescope  No.  132,  with  Level,  and  Clamp  and  Tangent. 
Price  as  shown,  $30.00. 

The  figure  shows  the  adaptation  of  a telescope  to  the  sight 
vanes  of  an  ordinary  compass,  which  was  invented  by  us  in 
1878,  and  has  since  come  into  very  general  use  with  the 
Solar  Compass.  The  telescope  is  about  9 inches  long,  and 


114 


THE  SOLAR  COMPASS. 


has  a power  of  18  to  20  diameters ; it  is  provided  of  course 
with  the  ordinary  cross-wires,  and  has  also  the  micrometer- 
wires  or  stadia  for  measuring  distances  as  described  in  our 
account  of  the  Engineers’  Transit.  In  the  cut  the  telescope 
is  shown  fitted  with  a level,  and  clamp  and  tangent,  and  to 
these  can  be  added  a vertical  circle  if  desired  for  the 
measurement  of  angles  of  elevation  and  depression.  For 
simple  sighting  the  level  and  circle  can  of  course  be  dis- 
pensed with,  but  in  the  use  of  the  micrometer-wires  the 
tangent  movement  is  very  desirable. 

When  measurements  are  to  be  recorded  in  chains  and 
links,  the  wires  should  be  made  to  cover  a foot  at  a distance 
of  66  feet ; if  recorded  in  feet,  they  should  cover  the  same 
interval  at  a distance  of  100  feet. 

The  rod  used  with  the  micrometer  should  be  graduated 
to  feet  and  decimals  of  a foot,  and  provided  with  two  tar- 
gets, the  upper  one  being  fixed  at  some  definite  point,  while 
the  lower  one  can  be  moved  as  the  surveyor  requires,  the 
distance  between  the  two  targets  being  accurately  read  off 
by  the  vernier  of  the  movable  one  ; or  a self-reading  rod  as 
hereafter  described  may  be  used  without  target  for  short 
distances. 

In  using  the  micrometer,  the  upper  wire  is  brought  by 
the  tangent-screw  precisely  upon  the  upper  or  stationary 
target,  while  the  lower  target  is  moved  up  or  down  until 
the  lower  wire  exactly  bisects  its  centre  line,  when  the  rod 
is  read,  and  the  distance  recorded. 

Advantages  of  the  Solar  Compass  in  Surveying . 

It  will  readily  occur  to  all  who  have  read  the  preceding 
description  of  the  Solar  Compass,  that  while  it  is  indispens- 
able in  the  surveys  of  public  lands,  it  also  possesses  im- 
portant advantages  over  the  magnetic  compass,  when  used 
in  the  ordinary  surveys  of  farms,  &e. 


THE  SOLAR  COMPASS. 


115 


For  not  only  can  lines  be  run  and  angles  oe  measured 
without  regard  to  the  diurnal  variation,  or  the  effect  of  local 
attraction,  but  the  bearings  being  taken  from  the  true 
meridian,  will  remain  unchanged  for  all  time. 

The  constant  uncertainty  caused  by  the  variation  of  the 
needle,  and  the  litigation  to  which  it  so  often  gives  rise, 
may  thus  be  entirely  prevented  by  the  use  of  the  Solar 
Compass  in  this  kind  of  work. 

It  is  also  said  by  those  familiar  with  the  use  of  this  instru- 
ment, that,  in  favorable  weather,  surveys  can  be  more  rapid- 
ly made  with  it  than  with  the  ordinary  needle  instrument; 
there  being  no  time  consumed  in  waiting  for  the  needle  to 
settle,  or  in  avoiding  the  errors  of  local  attraction. 

When  the  sun  is  obscured,  the  lines  may  be  run  by  the 
needle  alone,  it  being  always  kept  with  the  sun,  or  at  0 on 
its  arc,  and  thus  indicating  the  direction  of  the  true  meri- 
dian. 

The  sun,  however,  must  ever  be  regarded  as  the  most 
reliable  guide,  and  should,  if  possible,  be  taken  at  every 
station. 

It  is  with  the  design  of  making  the  principles  and  use  of 
the  Solar  Compass  intelligible  to  the  ordinary  surveyor,  that 
we  have  given  a more  extended  account  of  this  instrument 
than  of  the  others  previously  mentioned,  believing  that  when 
its  merits  become  better  understood,  it  will  come  into 
more  general  use. 

Super  iority  of  our  Solar  Compasses . 

The  Solar  Compass  as  hitherto  made,  though  planned 
with  great  ingenuity  in  its  general  arrangement,  was  still 
extremely  rude  in  its  mechanical  details  and  adjustments. 
Some  of  these  defects  which  are  apparent  on  inspection  of 
any  instrument,  as  hitherto  made  by  other  manufacturers, 


116 


THE  SOLAR  COMPASS. 


and  which  must  have  frequently  occurred  to  the  surveyor, 
we  will  now  enumerate. 

The  motion  of  the  plates  over  each  other  was  accom- 
panied with  so  much  friction,  that  in  turning  the  verniers 
around  the  limb,  the  whole  instrument  would  often  be 
moved  about  its  spindle. 

Again,  the  verniers  must  be  set,  and  the  sights  directed 
to  an  object  by  the  hand  alone,  a matter  of  no  little  difficulty 
when  single  minutes  of  a degree  werfc  to  be  set  off,  and  ac- 
curate observations  were  required. 

The  latitude  and  declination  arcs  must  also  be  moved  by 
hand,  and  the  verniers  set  to  single  minutes  in  the  same 
manner. 

The  points  in  which  we  claim  the  superiority  of  our  Solar 
Compass  over  any  hitherto  manufactured,  and  by  means  of 
which  the  defects  just  enumerated  are  entirely  removed, 
are  partially  shown  in  the  various  cuts  already  given,  and 
will  now  be  stated  in  detail. 

1.  A motion  of  the  horizontal  plates  almost  entirely  free  from  fric- 
tion, combined  with  perfect  solidity. 

2.  A fine  clamp  and  tangent  movement  to  the  divided  limb,  as 
shown  under  the  plate,  in  Fig.  25. 

3.  A tangent  movement  with  clamp,  for  the  declination  arc,  as 
shown  at  Jc. 

4.  A tangent  movement  with  clamp  to  the  latitude  arc,  as  shown 
at/. 

5.  A tangent  motion  for  the  whole  instrument  about  its  sockets,  as 
shown  in  Fig.  27. 

6.  Great  facility  of  adjustment,  and,  in  consequence,  an  important 
saving  of  time. 

7.  An  important  reduction  in  price,  while  still  furnishing  an  article 
greatly  improved. 

Weight  of  the  Solar  Compass. 

Solar  Compass,  including  leveling  head,  about  14|  lbs. 


THE  SOLAR  COMPASS. 


117 


A TABLE  OF  MEAN  REFRACTIONS  IN  DECLINATION. 

To  apply  on  the  declination  arc  of  Solar  Attachment  of 
either  Compasses  or  Transits. 


Computed  by  Edward  W.  Arms,  C.  E.,  for  Vvr.  & L.  E.  Gurley,  Troy,  N.  Y. 


p4 

ij 

CD 

DECLINATIONS. 

<5 

For  Latitude  30°. 

W 

P 

o 

w 

+ 20° 

+ 15° 

j +10° 

+ 5° 

0° 

-5° 

-10° 

-15° 

© 

<N 

1 

Oh. 

10" 

15" 

21" 

27" 

33" 

40" 

48" 

57" 

1'08" 

2 

14 

19 

25 

31 

38 

40 

54 

1'05 

1 18 

3 

20 

26 

32 

39 

47 

55 

POO 

1 19 

1 36 

4 

32 

39 

46 

52 

1'06 

P19 

1 35 

1 57 

2 29 

5 

POO 

r/io 

P24 

P52 

2 07 

244 

3 46 

5 43 

13  06 

For  Latitude  32 

30'. 

Oh. 

13" 

18" 

24" 

30" 

36" 

44" 

52" 

1'02" 

1'14" 

2 

17 

22 

28 

35 

42 

50 

POO 

1 11 

1 26 

3 

23 

29 

35 

43 

51 

l'Ol 

1 13 

1 28 

1 47 

4 

35 

43 

51 

l'Ol 

P13 

1 27 

1 46 

2 13 

2 54 

5 

1'03 

1'15 

1'31 

153 

2 20 

3 05 

4 25 

7 36 

For  Latitude  35°. 

Oh. 

15" 

21" 

27" 

33" 

40" 

48" 

57" 

1'08" 

1'21" 

2 

20 

25 

32 

38 

46 

55 

1'05 

1 18 

1 35 

3 

26 

33 

39 

47 

56 

P07 

1 21 

1 38 

2 00 

4 

30 

47 

56 

1'07 

1'20 

136 

1 59 

2 32 

3 25 

5 

P07 

1'20 

P38 

2 00 

2 34 

3 29 

5 14 

10  16 

For  Latitude  37 

30'. 

Oh. 

18" 

24" 

30" 

36" 

44" 

52" 

1'02" 

1'14" 

1'29" 

2 

22 

28 

35 

42 

59 

POO 

1 12 

1 26 

1 45 

3 

20 

36 

43 

52 

1'02 

1 14 

1 29 

1 49 

216 

4 

43 

51 

l'Ol 

P13 

1 27 

1 49 

2 14 

2 54 

4 05 

5 

I'll 

1'26 

1 51 

2 10 

2 49 

3 55 

6 15 

14  58 

For  Latitude  40°. 

Oh. 

21" 

27" 

33" 

49" 

48" 

57" 

1'08" 

1 '21" 

P39" 

2 

25 

32 

39 

46 

52 

1'06 

1 19 

1 35 

1 57 

3 

33 

40 

48 

57 

P03 

1 21 

1 38 

2 02 

2 36 

4 

47 

55 

POO 

1'19 

136 

1 58 

2 30 

3 21 

4 59 

5 

PIS 

1'31 

1 51 

220 

3 05 

4 25 

7 34 

25  18 

118 


THE  SOLAK  COMPASS. 


0 

DECLINATIONS. 

£ 

For  Latitude  42° 

30'. 

Ph 

t—1 

1 

1 

: c 
H 

+ 20° 

+ 15° 

+ 10 

+ 5° 

0° 

-5° 

-10° 

-15° 

1 

© 

! Oh. 

24" 

30" 

36" 

44" 

52" 

1'02" 

1'14" 

1'29" 

1'49" 

2 

28 

35 

39 

50 

l'OO 

1 12 

1 26 

1 45 

2 11 

3 

36 

43 

52 

1'02 

1 13 

1 29 

1 49 

217 

2 59 

4 

50 

l'OO 

I'll 

126 

144 

2 10 

2 49 

*55 

6 16 

5 

1/16 

136 

1 58 

2 30 

3 22 

5 00 

9 24 

For  Latitude  45°. 

Oh. 

27" 

33" 

40" 

48" 

57" 

1'08" 

1'21" 

1'39" 

2'02" 

2 

32 

39 

43 

52 

1'06 

1 19 

1 35 

1 57 

2 29 

3 

40 

47 

56 

1'07 

1 21 

1 38 

2 00 

2 34 

3 29 

4 

54 

1'04 

1'16 

1 33 

1 54 

2 24 

3 11 

4 38 

8 15 

5 

1'23 

141 

2 05 

2 41 

3 40 

5 40 

12  62 

For  Latitude  47 

3 30'. 

Oh. 

30" 

36" 

44" 

52" 

l/02" 

F14" 

1'29" 

1'49" 

2'18" 

2 

35 

42 

50 

F00 

1 12 

1 26 

1 45 

2 01 

2 51 

3 

43 

51 

l'Ol 

1 13 

1 28 

1 47 

2 15 

2 56 

4 08 

4 

56 

l'OO 

1 23 

140 

2 05 

2 40 

3 39 

5 37 

11  18 

5 

1'27 

146 

2 12 

2 52 

4 01 

6 30 

16  19 

For  Latitude  50°. 

Oh. 

33" 

40" 

48" 

57" 

1'08" 

1'21" 

1'39" 

2'02" 

2'36" 

2 

38 

46 

55 

1'06 

1 18 

1 35 

1 57 

2 28 

3 19 

3 

47 

56 

1'06 

1 19 

136 

2 29 

2 31 

3 23 

5 02 

4 

1'02 

1'14 

1 29 

148 

216 

2 58 

4 18 

6 59 

19  47 

5 

1 30 

1 51 

2 19 

304 

4 22 

7 28 

2410 

For  Latitude  52 

5 30'. 

Oh. 

36" 

44" 

52" 

1'02" 

1'14" 

1'29" 

1 '49" 

2'18" 

3'05" 

2 

43 

50 

59 

1 11 

126 

142 

2 23 

2 49 

3 55 

3 

50 

l'OO 

i'ii 

1 26 

145 

211 

2 51 

2 58 

6 22 

4 

1'05 

1 18 

1 35 

2 10 

2 28 

319 

4 53 

8 42 

5 

1 34 

1 56 

2 27 

316 

4 47 

8 52 

For  Latitude  55°. 

Oh. 

40" 

48" 

57" 

1'08" 

1'21" 

1'39" 

2'02" 

2'36" 

3'33" 

2 

46 

55 

1'05 

1 18 

1 34 

1 56 

2 30 

3 15 

4 47 

3 

55 

1'06 

1 19 

1 35 

1 58 

2 30 

3 21 

4 58 

9 19 

4 

F10 

1 23 

1 42 

2 06 

2 43 

344 

5 49 

12  41 

5 

137 

2 01 

2 34 

3 28 

5 15 

10  18 

For  Latitude  57' 

5 30'. 

Oh. 

44" 

52" 

1'02" 

1/14" 

1'29" 

1'49" 

2'18" 

3'05" 

4'37" 

2 

50 

59 

1 11 

1 25 

143 

2 09 

2 47 

3 51 

6 04 

3 

58 

l'lO 

1 24 

142 

2 07 

2 43 

3 45 

5 50 

12  47 

4 

I'll 

1 25 

143 

210 

2 50 

3 55 

6 14 

14  49 

5 

141 

2 06 

2 42 

3 42 

5 46 

12  26 

THE  RAILROAD  COMPASS. 


119 


THE  RAILROAD  COMPASS. 

This  instrument  is  a compass  of  the  highest  grade,  in 
which  by  the  addition  of  a divided  limb  and  verniers  the 
surveyor  is  enabled  to  take  angles,  and  run  lines  unaffected 
by  the  imperfections  of  the  magnetic  needle. 

Imperfections  of  the  Needle . 

These  may  arise  either  from  the  loss  of  magnetic  virtue 
in  the  poles,  the  blunting  of  the  centre-pin,  or  the  attrac- 
tion exerted  upon  it  by  bodies  of  iron,  whose  presence  may 
be  entirely  unsuspected. 

The  first  two  of  these  errors  may  be  easily  remedied  in 
the  manner  hereafter  described. 


Fig.  29. 

Price  as  shown  above,  with  two  verniers  to  limb,  5i-inch 
needle  and  jacob-staff  mountings,  $75.00. 


120 


THE  RAILROAD  COMPASS. 


Local  Attraction.—  The  third  and  most  frequent 
source  of  inaccuracy,  may  be  detected  by  taking  back  sights 
as  well  as  fore  sights,  upon  every  line  run  with  the  needle, 
and  by  the  agreement  of  the  bearings  determining  the  true 
direction  of  the  line. 

Sometimes  a compass  may  have  little  particles  of  iron 
concealed  within  the  surface  of  the  metal  circle  or  plates. 

It  is  the  business  of  the  maker  to  examine  every  instru- 
ment, in  search  of  this  defect,  by  trying  the  reversion  of 
the  needle  upon  all  points  of  the  divided  circle. 

If  the  needle  should  fail  to  reverse,  when  the  compass  is 
turned  half  around,  and  the  sights  directed  a second  time 
upon  any  object,  the  instrument  should  be  thrown  aside 
and  never  sold. 

Besides  the  difficulties  caused  by  the  above  imperfections, 
the  variation  of  the  needle  is  a frequent  source  of  annoy- 
ance. 

What  is  termed  the  secular  variation,  we  shall  soon  men- 
tion in  our  account  of  the  Vernier  Compass;  we  will  now 
speak  of  the 

Diurnal  Variation . — This  is  owing  to  the  influence 
of  the  sun,  which,  in  summer,  will  cause  the  needle  to  vary 
from  ten  to  fifteen  minutes  in  a few  hours,  when  exposed  to 
its  fullest  influence. 

To  guard  against  these  causes  of  inaccuracy  in  the  use  of 
needle  instruments,  the  surveyor  will  need  the  greatest  care 
and  attention;  and  yet,  with  all  the  precautions  that  can  be 
suggested,  the  difficulty  of  measuring  horizontal  angles  with 
certainty,  and  to  a sufficient  degree  of  minuteness  by  the 
needle  alone,  has  caused  a demand  to  be  felt  more  and  more 
sensibly  in  all  parts  of  the  country  for  instruments,  in  the 
use  of  which  the  surveyor  may  proceed  with  assured  accu- 
racy and  precision. 

Indeed,  in  Canada,  so  great  is  the  distrust  of  needle  in- 


THE  RAILROAD  COMPASS. 


121 


struments,  that  the  Provincial  Land  Surveyors  are  forbid- 
den to  use  an  instrument  in  their  land  surveys,  unless  it  is 
capable  of  taking  angles  independently  of  the  needle. 

And  though,  with  all  its  imperfections,  the  ordinary  com- 
pass, from  its  simplicity  and  convenience,  is  a very  valuable 
instrument,  and  therefore  will  always  be  used  where  land  is 
abundant  and  cheap,  yet  the  demand  for  instruments  of  a 
higher  class  is  constantly  increasing,  as  more  accurate  work 
is  required  ; and  to  supply  this  demand,  at  least  in  part, 
the  Railroad  Compass  was  devised. 

It  has,  of  course,  as  shown  in  Pig.  29,  the  main-plate, 
levels,  sights,  and  needle  of  the  ordinary  instrument,  and  in 
addition,  underneath  the  main-plate,  a divided  circle  or 
limb  by  which  horizontal  angles  to  single  minutes  can  be 
taken  independently  of  the  needle. 

The  arrangement  of  the  sockets  is  precisely  like  that  of 
the  Surveyors’  Transit  with  twTo  verniers  to  limb,  and  the 
plates  can  be  separated  and  replaced  in  the  same  manner. 

The  verniers  are  attached  to  the  under  surface  of  the 
main-plate,  the  openings  through  which  they  are  seen  being 
covered  with  slips  of  glass  to  protect  the  divisions  from 
dust  aud  moisture  ; only  one  of  the  verniers  is  shown  in 
the  cut. 

The  connection  between  the  two  plates  is  made  by  a 
clamp  and  tangent  movement  shown  at  e , by  which  they  can 
be  fastened  together  or  released  at  will,  or  moved  slowly 
around  each  other  as  may  be  desired  in  the  use  of  the  com- 
pass. 

The  needle  lifting-screw  is  shown  near  the  clamp-screw, 
on  the  same  end  of  the  plate. 

On  the  opposite  side  of  the  compass-circle  is  seen  the 
head,  a,  of  a pinion  working  into  a circular  rack  fixed  to 
the  edge  of  the  compass  circle,  and  thus  enabling  the  sur- 
veyor to  move  the  compass-circle  about  its  centre  in  setting 


122  THE  RAILROAD  COMPASS. 

off  the  variation  of  the  needle,  precisely  as  in  the  case  of  the 
vernier  compass. 

The  variation  is  read  to  single  minutes  by  a vernier  and 
divided  arc,  partially  shown  near  the  letter  S in  the  cut. 

Near  the  pinion-head  is  also  shown  a clamp-screw,  by 
which  the  circle  is  securely  fixed  when  moved  to  the  proper 
position. 

The  sockets  upon  which  the  plates  of  this  instrument 
turn  are  long  and  well  fitted,  and  the  movement  of  the  ver- 
nier plate  around  the  limb  is  almost  perfectly  free  from 
friction. 

The  Graduated  Circle  or  limb  is  divided  to  half 
degrees,  and  figured  in  two  rows,  viz  : from  0°  to  90°,  and 
from  0°  to  360°  ; sometimes  but  a single  series  is  used,  and 
then  the  figures  run  from  0°  to  360°,  or  from  0°  to  180°  on 
each  side. 

The  figuring,  which  is  the  same  upon  this  as  in  the  other 
angular  instruments  already  described,  is  varied  when  de- 
sired by  the  surveyor.  The  first*  method  is  our  usual  prac- 
tice. 

The  Verniers  are  double,  having  on  each  side  of  the 
zero  mark  thirty  equal  divisions  corresponding  precisely 
with  twenty-nine  half  degrees  of  the  limb  ; they  thus  read 
to  single  minutes,  and  the  number  passed  over  is  counted 
in  the  same  direction  in  which  the  vernier  is  moved. 

The  use  of  two  opposite  verniers  in  this  and  other  instru- 
ments gives  the  means  of  “ cross-questioning”  the  gradua- 
tions, the  perfection  with  which  they  are  centered,  and  the 
dependence  which  can  be  placed  upon  the  accuracy  of  the 
angles  indicated. 

The  Needle  of  this  instrument  is  five  or  five  and  a half 
inches  long,  and  made  precisely  like  those  previously  de- 
scribed. 

The  Adjustments  of  this  instrument,  with  which  the 


THE  RAILROAD  COMPASS. 


123 


surveyor  will  have  to  do,  as  those  of  the  sights,  levels, 
needle,  &c.,  will  be  described  in  the  account  of  the  Vernier 
Compass. 

To  Use  the  Railroad  Compass . 

It  can  be  set  upon  the  common  compass-ball,  or  still  bet- 
ter, the  tangent-ball  already  described,  placed  either  in  a 
jacob-staff  socket,  a compass  tripod,  or  the  leveling  socket 
and  tripod  as  shown  with  the  solar  compass. 

We  have  also  adapted  to  many  of  these  instruments  the 
leveling  tripod  head,  with  clamp  and  tangent  movement, 
and  this  is  preferable  to  any  other  support. 

To  Take  Horizontal  Angles.— First  level  the 
plate  and  set  the  limb  at  zero,  fix  the  sights  upon  one  of  the 
objects  selected,  and  clamping  the  whole  instrument  firmly 
to  the  spindle,  unclamp  the  vernier  plate  and  turn  it  with 
the  hand,  until  the  sights  are  brought  nearly  upon  the 
second  object ; then  clamp  to  the  limb,  and  with  the  tan- 
gent-screw fix  them  precisely  upon  it. 

The  number  of  degrees  and  minutes  read  off  by  the  ver- 
nier will  give  the  angle  between  the  two  objects  taken  from 
the  centre  of  the  instrument. 

It  will  be  understood  that  the  horizontal  angles  can  be 
taken  in  any  position  of  the  verniers,  with  reference  to  the 
zero  point  of  the  limb  ; we  have  given  that  above  as  being 
the  usual  method,  and  liable  to  the  fewest  errors. 

It  is  advisable  where  great  accuracy  is  required,  in  this 
and  other  instruments  furnished  with  two  verniers,  to  ob- 
tain the  readings  of  the  limb  from  both,  add  the  two  to- 
gether and  halve  their  sum ; the  result  will  be  the  mean  of 
the  two  readings,  and  the  true  angle  between  the  points 
observed. 

Such  a course  is  especially  necessary  when  the  readings 
of  the  verniers  essentially  disagree,  as  may  sometimes  hap- 


124 


THE  RAILROAD  COMPASS. 


pen  when  the  instrument  has  been  injured  by  an  acci- 
dent. 

Use  of  the  Needle . — In  taking  horizontal  angles  as 
just  described,  the  magnetic  bearings  of  the  two  objects  are 
often  noted,  and  thus  two  separate  readings  of  the  same 
angle,  one  by  the  limb,  the  other  by  the  needle,  are  ob- 
tained, to  be  used  as  checks  upon  each  other  to  prevent 
mistakes. 

To  Turn  Off  the  Variation  of  the  Needle.— 

Having  leveled  the  instrument,  set  the  limb  at  zero,  and 
place  the  sights  upon  the  old  line,  note  the  reading  of  the 
needle,  and  make  it  agree  with  that  given  in  the  field  notes 
of  the  former  survey,  by  turning  the  compass-circle  about 
its  centre  by  the  pinion  a. 

Now,  clamp  the  compass-circle  firmly  by  the  clamp- 
screw,  and  the  number  of  degrees  or  minutes  passed  over 
by  the  vernier  of  the  compass-circle  will  be  the  change  of 
variation  in  the  interval  between  the  two  surveys. 

To  Survey  with  this  instrument,  the  operator  should 
turn  the  south  side  of  the  compass-face  towards  his  person, 
and  having  brought  the  zeros  of  the  limb  and  vernier  plate 
in  contact,  clamp  them,  and  proceed  as  directed  in  our  ac- 
count of  the  Vernier  Compass. 

The  telescopic  sight  as  hereafter  described,  is  often  used 
with  the  Railroad  Compass  with  very  excellent  results. 

Of  course  it  will  be  understood  that  lines  can  be  run  and 
angles  measured  by  the  divided  limb  and  verniers,  independ- 
ently of  the  needle;  and,  in  localities  where  local  attrac- 
tion is  manifested,  this  is  very  desirable. 

The  accuracy  and  minuteness  of  horizontal  angles  in- 
dicated by  this  instrument,  together  with  its  perfect 
adaptation  to  all  the  purposes  to  which  the  Vernier  Com- 
pass can  be  applied,  have  brought  it  into  use  in  many 


THE  RAILROAD  COMPASS. 


125 


localities,  where  the  land  is  so  valuable  as  to  require  more 
careful  surveys  than  are  practicable  with  a needle  instru- 
ment. 


Railroad  Compass , One  Vernier  to  Limb . 

This  instrument  is  essentially  like  that  already  described, 
but  of  somewhat  simpler  construction  in  its  sockets,  and 
having  but  one  vernier  to  the  limb  ; and,  though  afforded 
at  a price  materially  lower  than  the  other,  it  is  still  in  every 
way  accurate  and  reliable. 

Size  and  Weight  of  the  Railroad  Compass , One  Vernier. 

We  make  but  one  size  of  this  instrument,  viz. : five  and 
a half  inch  needle  ; which,  including  the  brass  head  of  the 
jacob-staff,  weighs  ten  and  a half  pounds. 

Size  and  Weight  of  the  Railroad  Compass , Two  Verniers. 

Vie  make  two  sizes  of  this  instrument,  viz.:  five,  and 
five  and  a half  inch  needle  ; the  largest  size,  including  the 
brass  head  of  the  jacob-staff,  weighing  eleven  pounds,  and 
the  five-inch,  ten  and  a half  pounds. 

We  invite  especial  attention  to  the  different  styles  of  our 
Railroad  compasses,  believing  that  in  many  respects  they 
are  very  much  superior  to  any  other  compass  made,  having 
a horizontal  limb,  and  an  arrangement  by  which  the  varia- 
tion of  the  needle  can  be  readily  set  off  and  ascertained. 


126 


THE  VERNIER  COMPASS. 


THE  VERNIER  COMPASS. 

This  instrument,  represented  in  the  engraving  Fig.  30, 
has  its  compass-circle,  to  which  is  attached  a “ vernier,” 
movable  about  a common  centre  a short  distance  in  either 
direction,  thus  enabling  the  surveyor  to  set  the  zeros  of  the 
circle  at  any  required  angle  with  the  line  of  sights;  the 
number  of  degrees  contained  in  this  angle  or  the  “ varia- 
tion of  the  needle  ” being  read  off  by  the  vernier. 

The  Compass- Circle  in  this,  as  in  all  our  instru- 
ments, is  divided  to  half  degrees  on  its  upper  surface,  the 
whole  degree  marks  being  also  cut  down  on  the  inside  cir- 
cumference, and  is  figured  from  0 to  90,  on  each  side  of  the 
centre  or  “ line  of  zeros.  ” 

The  circle  and  face  of  the  compass  are  silvered. 

The  movement  of  the  circle  is  effected  either  by  a slow 
moving  or  “ tangent  screw,”  as  shown  in  the  engraving,  or 
by  a concealed  rack  and  pinion — the  head  of  which  projects 
from  the  under  side  of  the  main  compass-plate. 

When  the  variation  is  set  off  as  described,  the  circle  is 
securely  fastened  in  its  position  by  a clamping-nut  under- 
neath the  main-plate. 

Ball- Spindle. — The  compass  is  usually  fitted  to  a 
spindle  made  slightly  conical,  and  having  on  its  lower  end 
a ball  turned  perfectly  spherical,  and  confined  in  a socket 
by  a pressure  so  light  that  the  ball  can  be  moved  in  any 
direction  in  the  operation  of  leveling  the  compass. 

The  ball  is  placed  either  in  the  brass  head  of  the  jacob- 
staff,  or,  still  better,  in  the  compass-tripod  seen  in  the  en- 
graving of  the  Vernier  Transit  already  described. 

The  Jacob- Staff  mountings  which  are  furnished  with 
all  our  compasses,  and  packed  in  the  same  case,  consist  of 


THE  YERKIEK  COMPASS.  127 


Fig.  30. 

Price,  with  jacob-staff  mountings,  $40.00. 


128 


THE  VERNIER  COMPASS. 


the  brass  head  already  mentioned,  and  a shoe,  pointed  with 
steel,  so  as  to  be  set  firmly  in  the  ground. 

The  staff,  to  which  the  mountings  should  be  securely 
fastened,  is  procured  from  any  wheelwright,  or  selected  by 
the  surveyor  himself  from  a sapling  of  the  forest. 

The  Spirit  Levels  are  placed  at  right  angles  to 
each  other  so  as  to  level  the  plate  in  all  directions, 
and  are  balanced  upon  a pivot  underneath  the  middle  of 
the  tube,  so  as  to  be  adjustable  by  a common  screw- 
driver. 

The  Sights , or  sight-vanes,  have  fine  slits  cut  through 
nearly  their  whole  length,  terminated  at  intervals  by  large 
circular  apertures,  through  which  the  object  sighted  upon 
is  more  readily  found.  Sometimes  a fine  horse-hair  or  wire 
is  substituted  for  one  half  the  slit,  and  placed  alternately 
with  it  on  opposite  sights. 

Tangent  Seale . — The  right  and  left  hand  edges  of  the 
sights  of  our  compasses,  have  respectively  an  eye-piece,  and 
a series  of  divisions,  by  which  angles  of  elevation  and  de- 
pression, for  a range  of  about  twenty  degrees  each  way,  can 
be  taken  with  considerable  accuracy. 

Such  arrangement  is  very  properly  termed  a “tangent 
scale,”  the  divided  edges  of  the  north  sight  being  tangents 
to  segments  of  circles  having  their  centres  at  the  eye-pieces, 
and  their  points  of  contact  with  the  tangent  lines  at  the  zero 
divisions  of  the  scale. 

The  cut  shows  the  eye-piece  and  divisions  for  angles  of 
elevation;  those  for  angles  of  depression,  concealed  in  this 
cut,  are  seen  in  that  of  the  Plain  Compass. 

Clamp-Screw. — In  the  side  of  the  hollow  cylinder,  or 
socket  of  the  compass,  which  fits  to  the  ball-spindle,  is  a 
screw  by  which  the  instrument  may  be  clamped  to  the  spindle 
in  any  position. 

Spring-Catch. — Besides  the  clamp-screw,  we  now  have 


THE  VERNIER  COMPASS. 


129 


fitted  to  the  sockets  of  our  compasses  a little  spring-catch, 
which,  as  soon  as  the  instrument  is  set  upon  the  spindle, 
slips  into  a groove,  and  thus  removes  all  danger  of  falling 
when  the  instrument  is  carried. 

Needle- Lifter . — There  is  also  underneath  the  main 
plate  a needle-lifting  screw  which,  by  moving  a concealed 
spring,  raises  the  needle  from  the  pivot,  and  thus  prevents 
the  blunting  of  the  point  in  transportation. 

When  the  compass  is  not  in  use  it  is  the  practice  of  many 
surveyors  to  let  down  the  needle  upon  the  point  of  the 
centre-pin,  and  let  it  assume  its  position  in  the  magnetic 
meridian,  so  as  to  retain  or  even  increase  its  polarity. 

We  would  advise  in  addition,  that  after  the  needle  has 
settled  it  should  be  raised  against  the  glass,  in  order  not  to 
dull  the  point  of  suspension. 

Outheeper . — A small  dial  plate,  having  an  index  turned 
by  a milled  head  underneath,  is  used  with  this  and  the  other 
compasses  to  keep  tally  in  chaining. 

The  dial  is  figured  from  0 to  16,  the  index  being  moved 
one  notch  for  every  chain  run. 

Brass  Cover . — A brass  cover  is  fitted  over  the  glass 
of  the  compass,  and  serves  to  protect  it  from  accident,  as 
well  as  to  prevent  electric  disturbance. 

The  Telescopic  Sight  is  often  supplied  with  the 
various  sizes  of  the  Vernier  Compass,  and  its  adjustments 
and  use  will  be  found  in  our  account  of  the  Plain  Com- 
pass. 

Use  of  the  Vernier . 

The  superiority  of  the  vernier  over  the  plain  compass  con- 
sists in  its  adaptation  to  the  retracing  the  lines  of  an  old 
survey,  and  to  the  surveys  of  the  U.  S.  public  lands,  where 
the  lines  are  based  on  a true  meridian. 


130 


THE  VERNIER  COMPASS. 


Variation  of  the  Needle . 

It  is  well  known  that  the  magnetic  needle,  in  almost  all 
parts  of  the  United  States,  points  more  or  less  to  the  east  or 
west  of  a true  meridian,  or  north  and  south  line. 

This  deviation,  which  is  called  the  Variation  or 
Declination  of  the  needle,  is  not  constant,  but  increases 
or  decreases  to  a very  sensible  amount  in  a series  of  years. 

Thus  at  Troy,  1ST.  Y.,  a line  bearing  in  1865,  N.  31°  E., 
would  in  1883,  with  the  same  needle,  have  a bearing  of 
about  N.  32°  E.,  the  needle  having  thus  in  that  interval 
traveled  a full  degree  to  the  west. 

For  this  reason,  therefore,  in  running  over  the  lines  of  a 
farm  from  field  notes  of  some  years  standing,  the  surveyor 
would  be  obliged  to  make  an  allowance,  both  perplexing  and 
uncertain,  in  the  bearing  of  every  line. 

To  avoid  this  difficulty  the  vernier  was  devised,  the 
arrangement  of  which  we  shall  now  describe. 

The  Vernier  is  divided  on  its  edge  to  thirty  equal 
parts,  and  figured  in  two  series  on  each  side  of  the  centre 
line. 

In  the  same  plane  with  the  vernier  is  an  arc  or  limb,  fixed 
to  the  main  plate  of  the  compass,  and  graduated  to  half 
degrees. 

The  surfaces  of  both  vernier  and  limb  are  silvered. 

On  the  vernier  are  thirty  equal  divisions,  which  exactly 
correspond  in  length  with  thirty-one  of  the  half  degrees  of 
the  limb. 

Each  division  of  the  vernier  is,  therefore,  one-thirtieth  or, 
in  other  words,  one  minute  longer  than  a single  division  of 
the  limb. 

To  Read  the  Vernier. — In  “reading”  the  vernier, 
if  it  is  moved  to  the  right,  count  the  minutes  from  its  zero 


THE  VERNIER  COMPASS. 


131 


point  to  the  left,  and  vice  versa.  Proceed  thus  until  a 
division  on  the  vernier  is  found  exactly  in  line  with  another 
on  the  limb,  and  the  lower  row  of  figures  on  the  vernier 
will  give  the  number  of  minutes  passed  over.  When  the 
vernier  is  moved  more  than  fifteen  minutes  to  either  side, 
the  number  of  the  additional  minutes  up  to  thirty  or  one- 
half  degree  of  the  limb  is  given  by  the  upper  row  of  figures 
on  the  opposite  side  of  the  vernier. 

To  read  beyond  thirty,  add  the  minutes  given  by  the 
vernier  to  that  number,  and  the  sum  will  be  the  correct 
reading. 

In  all  cases  when  the  zero  point  of  the  vernier  passes  a 
whole  degree  of  the  limb,  this  must  be  added  to  the  minutes, 
in  order  to  define  the  distance  over  which  the  vernier  has 
been  moved. 

To  Turn  Off  the  Variation . — It  will  now  be  seen 
that  the  surveyor  having  the  vernier  compass,  can  by  moving 
the  vernier  to  either  side,  and  with  it  of  course  the  compass- 
circle  attached,  set  the  compass  to  any  variation. 

He  therefore  places  his  instrument  on  some  well-defined 
line  of  the  old  survey,  and  turns  the  tangent-screw  until  the 
needle  of  his  compass  indicates  the  same  bearing  as  that 
given  in  the  old  field-notes  of  the  original  survey. 

Then  screwing  up  the  clamping  nut  underneath  the  ver- 
nier, he  can  run  all  the  other  lines  from  the  old  field-notes 
without  further  alteration. 

The  reading  of  the  vernier  on  the  limb  in  such  a case  would 
give  the  change  of  variation  at  the  two  different  periods. 

The  variation  of  the  needle  at  any  place  being  known,  a 
true  meridian,  or  north  and  south  line,  may  be  run  by  mov- 
ing the  vernier  to  either  side,  as  the  variation  is  east  or 
west,  until  the  arc  passed  over  on  the  limb  is  equal  to  the 
angle  of  variation;  and  then  turning  the  compass  until  the 
needle  is  made  to  cut  the  zeros  on  the  divided  circle,  when 


132 


THE  VERNIER  COMPASS. 


the  line  of  the  sights  would  give  the  direction  of  the  true 
meridian  of  the  place. 

Such  a change  in  the  position  of  the  vernier  is  necessary 
in  surveying  the  U.  S.  public  lands,  which  are  always  run 
from  the  true  meridian. 

The  Line  of  No  Variation 9 as  it  is  called,  or  that 
upon  which  the  needle  will  indicate  a true  north  and  south 
direction,  is  situated  in  the  United  States,  nearly  in  an 
imaginary  line  drawn  from  the  middle  of  Lake  Erie  to 
Cape  Hatteras,  on  the  coast  of  North  Carolina. 

A compass-needle,  therefore,  placed  east  of  this  line 
would  have  a variation  to  the  west,  and  when  placed  west 
of  the  line,  the  variation  would  be  to  the  east,  and  in  both 
cases  the  variation  would  increase  as  the  needle  was  carried 
farther  from  the  line  of  no  variation. 

Thus,  in  Minnesota  the  variation  is  from  15°  to  16°  to 
the  east,  while  in  Maine  it  is  from  17°  to  18°  to  the  west. 

At  Troy,  in  the  present  year,  1884,  the  variation  is  about 
10°  to  the  west,  and  is  increasing  in  the  same  direction 
from  two  to  three  minutes  annually. 

To  Lead  to  Minutes. — A less  important  use  of  the 
vernier  is  to  give  a reading  of  the  needle  to  single  minutes, 
which  is  obtained  as  follows : 

First  be  sure,  as  in  all  observations,  that  the  zero  of  the 
vernier  exactly  corresponds  with  that  of  the  limb  ; then 
noting  the  number  of  whole  degrees  given  by  the  needle, 
move  back  the  compass-circle  with  the  tangent-screw  until 
the  nearest  whole  degree-mark  is  made  to  coincide  with  the 
point  of  the  needle,  read  the  vernier  as  before  described, 
and  this  reading  added  to  the  whole  degrees  will  give  the 
bearing  to  minutes. 


6 


THE  VERNIER  COMPASS. 


133 


To  Adjust  the  Compass . 

The  Levels . — First  bring  the  bubbles  into  the  centre, 
by  the  pressure  of  the  hand  on  different  parts  of  the  plate, 
and  then  turn  the  compass  half-way  around;  should  the 
bubbles  run  to  the  end  of  the  tubes,  it  would  indicate  that 
those  ends  were  the  highest ; lower  them  by  tightening  the 
screws  immediately  under,  and  loosening  those  under  the 
lowest  ends  until,  by  estimation,  the  error  is  half  removed  ; 
level  the  plate  again,  and  repeat  the  first  operation  until  the 
bubbles  will  remain  in  the  centre,  during  an  entire  revolu- 
tion of  the  compass. 

The  Sights  may  next  be  tested  by  observing  through 
the  slits  a fine  hair  or  thread,  made  exactly  vertical  by  a 
plumb.  Should  the  hair  appear  on  one  side  of  the  slit,  the 
sight  must  be  adjusted  by  filing  off  its  under  surface  on 
that  side  which  seems  the  highest. 

The  Needle  is  adjusted  in  the  following  manner  : Hav- 
ing the  eye  nearly  in  the  same  plane  with  the  graduated 
rim  of  the  compass-circle,  with  a small  splinter  of  wood  or 
a slender  iron  wire,  bring  one  end  of  the  needle  in  line 
with  any  prominent  division  of  the  circle,  as  the  zero,  or 
ninety  degree-mark,  and  notice  if  the  other  end  corres- 
ponds with  the  degree  on  the  opposite  side ; if  it  does,  the 
needle  is  said  to  “cut”  opposite  degrees;  if  not,  bend  the 
centre-pin  by  applying  a small  brass  wrench,  furnished 
with  our  compasses,  about  one-eighth  of  an  inch  below  the 
point  of  the  pin,  until  the  ends  of  the  needle  are  brought 
into  line  with  the  opposite  degrees. 

Then,  holding  the  needle  in  the  same  position,  turn  the 
compass  halfway  around,  and  note  whether  it  now  cuts  op- 
posite degrees  ; if  not,  correct  half  the  error  by  bending  the 
needle,  and  the  remainder  by  bending  the  centre-pin. 


134 


THE  VERNIER  COMPASS. 


The  operation  should  be  repeated  until  perfect  reversion 
is  secured  in  the  first  position. 

This  being  obtained,  it  may  be  tried  on  another  quarter 
of  the  circle ; if  any  error  is  there  manifested,  the  correc- 
tion must  be  made  in  the  centre-pin  only,  the  needle  being 
already  straightened  by  the  previous  operation. 

AVhen  again  made  to  cut,  it  should  be  tried  on  the  other 
quarters  of  the  circle,  and  corrections  made  in  the  same 
manner  until  the  error  is  entirely  removed,  and  the  needle 
will  reverse  in  every  point  of  the  divided  surface. 

To  Use  the  Compass . 

In  using  the  compass,  the  surveyor  should  keep  the 
south  end  towards  his  person,  and  read  the  bearings  from 
the  north  end  of  the  needle.  He  will  observe  that  the  E 
and  W letters  on  the  face  of  the  compass  are  reversed  from 
their  natural  position,  in  order  that  the  direction  of  the 
line  of  sight  may  be  correctly  read. 

The  compass-circle  being  graduated  to  half-degrees,  a 
little  practice  will  enable  the  surveyor  to  read  the  bearings 
to  quarters,  or  even  finer — estimating  with  his  eye  the 
space  bisected  by  the  point  of  the  needle,  and  as  this  is  as 
low  as  the  traverse  table  is  usually  calculated,  it  is  the  gen- 
eral practice. 

Sometimes,  however,  a small  vernier  is  placed  upon  the 
south  end  of  the  needle,  and  reads  the  circle  to  five  minutes 
of  a degree — the  circle  being  in  that  case  graduated  to 
whole  degrees. 

This  contrivance,  however,  is  quite  objectionable  on  ac- 
count of  the  additional  weight  imposed  on  the  centre-pin, 
and  the  difficulty  of  reading  a vernier  which  is  in  constant 
vibration ; it  is  therefore  but  little  used. 

To  Take  Angles  of  Elevation.— Having  first 
leveled  the  compass,  bring  the  south  end  towards  you,  and 


THE  VERNIER  COMPASS. 


135 


place  the  eye  at  the  little  button,  or  eye-piece,  on  the  right 
side  of  the  south  sight,  and  with  the  hand  fix  a card  on  the 
front  surface  of  the  north  sight,  so  that  its  top  edge  will  be 
at  right  angles  to  the  divided  edge,  and  coincide  with  the 
zero  mark;  then  sighting  over  the  top  of  the  card,  note 
upon  a flagstaff  the  height  cut  by  the  line  of  sight ; then 
move  the  staff  up  the  elevation,  and  carry  the  card  along 
the  sight  until  the  line  of  sight  again  cuts  the  same  height 
on  the  staff,  read  off  the  degrees  and  half-degrees  passed 
over  by  the  card,  and  you  will  have  the  angle  required. 

For  Angles  of  Depression . — Proceed  in  the  same 
manner,  using  the  eye-piece  and  divisions  on  the  opposite 
sides  of  the  sights,  and  reading  from  the  top  of  the 
sights. 

When  the  Instrument  is  to  be  used  in  making  new 
surveys,  the  vernier  should  be  set  at  zero  and  securely 
clamped  by  screwing  up  the  nut  beneath  the  plate. 

In  surveying  old  lines,  the  change  of  the  variation  of  the 
needle  should  be  ascertained  by  setting  the  compass  on 
some  one  well-defined  line  of  the  tract,  and  making  the 
bearing  to  agree  with  that  of  the  old  survey,  by  moving  the 
circle  as  already  described. 

Then  the  circle  can  be  clamped,  and  the  old  lines  re- 
traced from  the  bearings  given  by  the  original  surveyor. 

When  the  variation  of  the  needle  is  known,  it  can  be  set 
off  by  the  vernier,  and  the  compass  used  to  run  a true 
meridian  by  the  needle. 

Electricity . — A little  caution  is  necessary  in  handling 
the  compass,  that  the  glass  covering  be  not  excited  by  the 
friction  of  cloth,  silk,  or  the  hand,  so  as  to  attract  the 
needle  to  its  under  surface. 

When,  however,  the  glass  becomes  electric,  the  fluid  may 
be  removed  by  breathing  upon  it,  or  touching  different 
parts  of  its  surface  with  the  moistened  finger. 


136 


THE  YERHIER  COMPASS. 


An  ignorance  of  this  apparently  trifling  matter  has  caused 
many  errors  and  perplexities  in  the  practice  of  the  inexpe- 
rienced surveyor. 

Repairs  of  the  Compass . 

To  enable  the  surveyor  to  make  such  repairs  as  are  pos- 
sible without  having  recourse  to  an  instrument  maker,  we 
here  add  a few  simple  directions. 

1.  The  Needle. — It  may  sometimes  happen  that  the 
needle  has  lost  its  polarity,  and  needs  to  be  remagnetized  ; 
this  is  effected  in  the  following  manner  : 

The  operator  being  provided  with  an  ordinary  permanent 
magnet,*  and  holding  it  before  him,  should  pass  with  a 
gentle  pressure  each  end  of  the  needle  from  centre  to 
extremity  over  the  magnetic  pole,  describing  before  each 
pass  a circle  of  about  six  inches  radius,  to  which  the  surface 
of  the  pole  is  tangent,  drawing  the  needle  towards  him,  and 
taking  care  that  the  north  and  the  south  ends  are  applied  to 
the  opposite  poles  of  the  magnet. 

Should  the  needle  be  returned  in  a path  near  the  magnetic 
pole,  the  current  induced  by  the  contact  of  the  needle  and 
magnet,  in  the  pass  just  described,  would  be  reversed,  and 
thus  the  magnetic  virtue  almost  entirely  neutralized  at  each 
operation. 

When  the  needle  has  been  passed  about  twenty-five  times 
in  succession,  in  the  manner  just  described,  it  may  be  con- 
sidered as  fully  charged. 

A fine  brass  wire  is  wound  in  two  or  three  coils  on  the 
south  end  of  the  needle,  and  may  be  moved  back  or  forth 
in  order  to  counterpoise  the  varying  weight  of  the  north 
end. 

2.  The  Centre-Tin . — This  should  occasionally  be 


* A magnet  suitable  for  this  purpose  costs  25  to  50  cents. 


THE  VERNIER  COMPASS. 


137 


examined,  and  if  much  dulled,  taken  out  with  the  brass 
wrench,  already  spoken  of,  or  with  a pair  of  pliers,  and 
sharpened  on  a hard  oil-stone — the  operator  placing  it  in 
the  end  of  a small  stem  of  wood,  or  a pin-vise,  and  delicately 
twirling  it  with  the  fingers  as  he  moves  it  back  and  forth  at 
an  angle  of  about  30  degrees  to  the  surface  of  the  stone. 

When  the  point  is  thus  made  so  fine  and  sharp  as  to  be 
invisible  to  the  eye,  it  should  be  smoothed  by  rubbing  it  on 
the  surface  of  a soft  and  clean  piece  of  leather., 

3.  To  Put  in  a New  Glass . — Unscrew  the  “ bezel 
ring”  which  holds  it,  and  with  the  point  of  a knife-blade, 
spring  out  the  little  brass  ring  above  the  glass,  remove  the 
old  glass  and  scrape  out  the  putty  ; then  if  the  new  glass 
does  not  fit,  smooth  off  its  edges  by  holding  it  obliquely  on 
the  surface  of  a grindstone  until  it  will  enter  the  ring 
easily ; then  put  in  new  putty,  spring  in  the  brass  ring,  and 
the  operation  will  be  complete. 

4.  To  Replace  a Spirit-Level. — Take  out  the  screws 
which  hold  it  on  the  plate,  pull  off  the  brass  ends  of  the 
tube,  and  with  a knife-blade  scrape  out  the  plaster  from  the 
tube ; then  with  a stick  made  a little  smaller  than  the 
diameter  of  the  tube,  and  with  its  end  hollowed  out,  so  that 
it  will  bear  only  on  the  broad  surface  of  the  level  vial,  push 
out  the  old  vial  and  replace  it  with  a new  one,  taking  care 
that  the  crowning  side,  which  is  usually  marked  with  a file 
on  the  end  of  the  vial,  is  placed  on  the  upper  side. 

When  the  vial  does  not  fit  the  tube  it  must  be  wedged 
up  by  putting  under  little  slips  of  paper  until  it  moves  in 
snugly. 

After  the  vial  is  in  its  place,  put  around  its  ends  a little 
boiled  plaster,  mixed  with  water  to  the  consistency  of  putty, 
taking  care  not  to  allow  any  to  cover  the  little  tip  of  the 
glass,  then  slip  in  the  brass  ends  and  the  operation  will  be 
completed. 


138 


THE  VERMIER  COMPASS. 


A little  beeswax,  melted  and  dropped  upon  the  ends  of  the 
vial,  is  equally  as  good  as  the  boiled  plaster,  and  often  more 
easily  obtained. 

We  would  here  remark  that  an  extra  glass  and  level  vials 
are  always  furnished,  free  of  charge,  with  every  new  com- 
pass and  transit  sent  out  of  our  works. 


Sizes  of  the  Vernier  Compass . 

We  make  three  sizes  of  this  compass,  having  needles  of 
four,  five  and  six  inches  long  respectively,  the  main  plates 
of  the  two  largest  being  over  fifteen  inches  long  ; and  of  the 
smallest  size,  thirteen  inches,  the  sights  of  the  last  are  also 
about  an  inch  shorter. 

In  the  four  and  five  inch  Vernier  Compasses,  the  variation 
arc  is  within  the  compass-circle  like  that  of  the  railroad  com- 
pass before  described,  and  the  variation  is  set  off  to  minutes 
by  a pinion-head  underneath  the  plate ; the  circle  is  also 
clamped  at  any  variation  by  a screw  placed  opposite  the 
pinion. 


Weight  of  the  Vernier  Compasses . 

The  average  weights  of  the  different  sizes,  including  the 
brass  head  of  the  jacob-staff,  beginning  with  the  smallest, 
are  respectively  5^,  7-J-  and  9-J-  pounds. 


THE  PLAIH  COMPASS. 


139 


Fig.  31. 

Price,  with  6-inch  needle  and  jacob-staff  mountings,  $35.00. 

As  represented  in  Fig.  31,  the  Plain  Compass  has  a 6-inch 
needle,  and  is  furnished  with  levels,  sight-vanes,  socket,  &c. 

The  compass-box  is  now  in  the  same  piece  with  the  main 
plate,  and  the  instrument  is  used  mainly  in  the  surveys  of 
new  lines,  or  in  the  preparation  of  maps,  where  the  variation 
of  the  needle  is  not  required. 

The  Adjustments  and  use  of  the  Plain  Compass 
are  substantially  the  same  as  those  of  the  instrument  just 
described. 

Telescopic  Sights. 

We  have  for  years  supplied  for  this  and  the  other  com- 
passes a telescope  fitted  to  the  sight-vanes,  which  could  be 
put  on  and  removed  at  will,  and  it  has  met  with  very  great 


140 


THE  PLAIK  COMPASS. 


approval,  hundreds  of  them  being  now  in  use  in  different 
parts  of  the  country;  this  attachment  we  will  now  more 
fully  describe. 


THE  TELESCOPIC  SIGHT. 


Price  of  Telescope  No.  131  as  shown,  with  movable  band 
for  attaching,  $17.00. 

This  valuable  improvement  of  the  Surveyors5  Compass 
consists  of  a telescope  furnished  with  the  usual  cross- 
wires, &c.,  and  attached  to  a movable  band,  which,  as 
shown  in  the  engraving,  can  be  slipped  over  the  sight  of  a 
compass,  clamped  at  any  point  desired,  and  put  in  adjust- 


THE  PLAIH  COMPASS. 


141 


ment  by  any  person  who  has  a screw-driver  and  a steel 
adjusting  pin. 

To  put  this  attachment  in  place,  slip  the  band  over  the 
south  sight  of  the  compass,  having  (as  shown  in  the  cut) 
the  telescope  on  the  right  hand  and  the  front  clamp-screw 
on  the  outer  surface  of  the  sight ; and  place  the  band  as  low 
as  will  allow  the  telescope  to  revolve  in  either  direction 
without  striking  the  compass.  This  place  should  be  marked 
by  a line  across  the  sight,  that  the  band  may  be  set  at  the 
same  point  in  subsequent  use. 

To  fasten  the  band  to  the  sight,  first  bring  up  the  clamp- 
screw  in  front  with  a pressure  just  sufficient  to  hold  the  band 
to  its  place,  then  tighten  the  screw  on  the  left  until  the  band 
is  brought  up  against  the  right  edge  of  the  sight,  and  finally 
touch  the  front  clamp-screw  again,  when  the  fastening  will 
be  complete. 

To  put  the  telescope  in  focus,  turn  the  end  of  the  eye- 
piece either  back  or  forth  by  the  thumb  and  forefinger  until 
by  the  spiral  motion  of  the  tube  the  cross-wires  are  brought 
into  distinct  view  ; the  object-glass  is  then  moved  in  either 
direction  by  the  pinion  on  the  side  of  the  telescope  until 
the  object  is  clearly  seen. 

The  Adjustments 

Of  the  Telescopic  Sight  are  as  follows  : 

(1)  To  make  the  telescope  axis  horizontal. 

(2)  To  bring  the  optical  axis  of  telescope  into  a position 
at  right  angles  to  the  axis. 

(3)  To  make  the  optical  axis  of  telescope  cut  the  same 
line  as  the  sight-vanes  of  compass. 

To  make  these  adjustments — and,  indeed,  to  do  any  cor- 
rect work  with  a compass — the  spindle  should  be  well- 
fitted,  and  the  level-bubbles  remain  in  the  centre  when  the 


142 


THE  PLAIN  COMPASS. 


instrument  is  revolved  upon  its  spindle ; the  sights  also 
should  trace  a plumb-line  when  the  compass  is  level. 

To  make  the  first  adjustment  : 

(1)  The  compass  being  in  good  order,  first  bring  the 
levels  into  the  centre  ; place  the  band  in  position  upon  the 
sight,  as  before  described  ; bring  the  telescope  into  focus 
and  set  the  vertical  cross-wire  on  the  vertical  edge  of  a 
building,  distant  from  fifty  to  sixty  feet,  and  at  a point 
near  the  ground  ; clamp  the  compass  to  the  spindle,  and 
raise  the  telescope  to  the  top  of  the  building.  If  the  wire 
strikes  to  the  right  of  the  edge,  it  shows  that  the  right  end 
of  the  telescope  axis  is  lowest. 

To  raise  it,  loosen  the  clamp-screw  on  the  left,  and  with 
a small  screw-driver  turn  in  the  little  screw  on  the  right 
side  of  the  band  and  under  the  axis  until  the  correction  is 
made. 

If  the  cross-wire  strikes  to  the  left  when  the  telescope  is 
raised,  proceed  exactly  the  reverse  in  making  the  correction 
until  the  wire  will  follow  the  edge  from  one  end  to  the 
other,  when  the  adjustment  will  be  complete.  If  the  ver- 
tical cross-wire  is  not  parallel  with  the  edge,  loosen  the  cap- 
stan-head screws,  and  turn  the  ring  by  the  screw-heads 
until  the  correction  is  made  ; and  finally  tighten  the 
screws. 

(2)  To  make  the  second  adjustment — that  is,  to  bring 
the  optical  axis  into  a position  at  right  angles  to  the  axis  of 
the  telescope  so  that  the  cross-wires  will  indicate  two  points 
in  opposite  directions  in  the  same  straight  line — proceed  as 
follows : 

Having  the  instrument  level,  find  or  place  two  objects,  one 
on  each  side  of  the  compass,  and  from  three  hundred  to  four 
hundred  feet  distant  from  it,  which  the  sight-vanes  will  in- 
tersect ; clamp  to  the  spindle  and  sight  through  the  tele- 
scope at  either  of  the  objects  ; if  the  vertical  wire  strikes  to 


THE  PLAIN  COMPASS. 


143 


the  right,  loosen  the  clamp-screw  in  front,  and  with  the 
screw-driver  turn  in  the  little  screws  set  in  the  front  side 
of  the  band,  one  on  each  side  of  the  telescope  axis,  until  the 
vertical  wire  bisects  the  object — looking  again  through  the 
vanes  to  see  that  the  compass  has  not  moved  on  its  spindle, 
so  that  the  same  object  is  seen  through  both  telescope  and 
sights.  If,  however,  the  cross-wire  should  strike  to  the 
left  of  the  object,  proceed  in  a manner  exactly  the  reverse 
until  the  error  is  corrected. 

Then,  without  disturbing  the  compass,  revolve  the  tele- 
scope and  sight  to  the  object  in  the  opposite  direction  ; if 
the  vertical  wire  strikes  to  either  side,  half  the  error  must 
be  removed  by  the  cross-wire  screws  shown  on  the  outside 
of  the  telescope — first  loosening  the  screw  on  the  side 
towards  which  the  wire  is  to  be  moved,  and  then  tightening 
the  opposite  screw  until  one-half  the  error  is  corrected, 
and  the  remainder  by  the  two  small  screws  in  front  of  the 
band. 

Having  made  the  correction,  sight  again  through  .the 
vanes  and  telescope,  repeating  the  operation  until  the  error 
is  entirely  removed,  when  the  adjustment  will  be  com- 
plete. 

It  should  be  here  remarked  that  the  adjustment  just 
described,  and  which  is  usually  termed  the  adjustment  of 
the  line  of  collimation,  is  fully  described  in  the  account  of 
the  various  transit  instruments  already  given,  and  may  be 
effected  with  this  attachment  by  the  telescope  alone,  without 
reference  to  the  sight-vanes — precisely  as  directed  in  the 
adjustments  of  a transit  instrument.  It  is  always  made  by 
us  before  the  attachment  passes  out  of  our  hands,  and  need 
not  again  be  disturbed  except  in  cases  of  accident  or  care- 
less interference  with  the  cross-wire  screws ; but  in  any 
event  it  can  be  easily  effected  by  any  surveyor  in  a few  mo- 
ments, and  with  very  little  practice. 


144 


THE  PLAIK  COMPASS. 


(3 ) If  the  surveyor  has  made  the  second  adjustment,  as 
just  described,  he  has  already  put  the  optical  axis  of  the 
telescope  in  line  with  the  sights,  and  so  effected  the  final 
adjustment ; hut  if  not,  and  especially  if  the  telescope  sight 
is  to  be  applied  by  himself  to  a compass  to  which  the  maker 
has  not  fitted  it,  then  he  will  proceed  as  follows  : 

Having  the  compass  level,  direct  the  sights  to  some 
clearly  defined  object — as  a post,  staff,  or  vertical  bar  of  a 
window — some  three  hundred  or  four  hundred  feet  distant, 
clamp  to  spindle  and  observe  the  same  with  the  telescope. 

If  the  vertical  wire  strikes  to  either  side,  remove  the 
error  by  the  two  screws  in  front  of  the  band,  as  already 
described  in  the  previous  adjustment,  until  the  correction 
is  made ; and  the  telescope  will  then  bisect  the  same  object 
in  either  direction,  as  is  indicated  by  the  sight-vanes. 

Of  course,  when  the  telescopic  sight  is  fitted  by  us,  either 
to  a new  or  old  compass,  the  adjustments  above  described 
are  all  completed  before  the  instrument  is  sent  out  of  our 
hands,  but  we  have  been  thus  minute  in  our  description  of 
them  in  order  that  surveyors  sending  for  this  attachment 
may  be  enabled  to  apply  it  to  their  own  compasses  without 
further  trouble  or  expense. 

When  the  adjustments  are  complete  the  attachment  can  be 
put  in  place  on  the  sights,  removed  and  replaced  again  in 
a moment,  and  without  danger  of  derangement  in  any  of 
its  parts. 

The  advantages  of  the  telescope  over  the  ordinary  sight- 
vanes  will  be  apparent  to  every  one  who  has  ever  seen 
them  compared,  or  who  has  given  the  matter  a moment’s 
reflection. 

Much  longer  sights  can  be  taken,  either  fore  or  back,  and 
lines  run  up  and  down  steep  hillsides  with  the  same  facil- 
ity as  on  level  ground,  and  all  with  more  accuracy,  and 
with  inexpressible  relief  to  the  eyes  of  the  surveyor,  so  often 


THE  PLAIN  COMPASS. 


145 


severely  strained  by  the  use  of  the  sight-vanes  of  the  ordi- 
nary compass. 

Indeed,  it  may  be  said  that  every  compass  can  with  this 
simple  attachment  be  transformed  into  a transit  compass  at 
will,  and  thus  all  the  advantages  of  the  telescope  brought 
within  the  reach  of  every  surveyor  at  comparatively  trifling 
cost. 

The  optical  axis  of  the  telescopic  sight  is  at  one  side  of 
the  line  of  sight  of  the  sight-vanes,  but  parallel  to  it.  The 
difference  between  a sight  taken  with  the  sight-vanes,  and 
one  taken  with  the  telescope,  is,  at  a distance  of  two  hun- 
dred feet,  about  two  minutes, — so  small  that  it  may  be  dis- 
regarded in  any  survey  made  with  the  magnetic  needle. 

If  all  lines  are  run  with  the  telescopic  sight,  the  angles 
measured  will  be  accurate,  as  even  this  slight  difference  is 
entirely  eliminated. 

When  furnished  with  a new  instrument,  it  ]s  packed  in 
the  box,  like  the  sights,  etc.,  or  it  can  be  safely  forwarded 
by  mail  to  any  part  of  the  country,  securely  packed  in  a 
suitable  case,  in  which  it  may  be  kept  when  not  in  use. 

We  make  three  styles  of  the  telescopic  sight;  see  Price 
List,  Nos.  130,  131,  132. 

The  stadia  wires  alluded  to  in  No.  132  are  two  horizontal 
parallel  cross-wires,  one  on  each  side  of  the  centre  wire,  and 
each  fastened  to  a movable  piece  which  is  controlled  by  a 
screw  on  the  outside  of  the  telescope.  The  distance  be- 
tween the  stadia  wires  can  thus  be  adjusted  so  as  to  cover  a 
certain  vertical  space  on  a divided  rod,  held  at  a given 
distance  from  the  centre  of  the  instrument,  usually  one  foot 
or  one  link  on  the  rod  to  one  hundred  feet  or  one  hundred 
links  in  distance — as  more  fully  described  in  our  account 
of  other  instruments. 


146 


THE  PLAIN  COMPASS. 


Attachments  to  Telescopic  Sights. 

In  the  account  of  the  Solar  Compass  we  have  already 
given  a figure  and  description  of  telescopic  sight  with  stadia, 
level,  and  clamp  and  tangent,  and  these  with  vertical  circle 
reading  to  five  minutes,  are  often  applied  and  found  to  be 
serviceable. 

Sizes  and  Weights  of  the  Plain  Compass. 

Three  different  sizes  of  this  instrument  are  in  common 
use,  having  respectively,  four,  five,  and  six-inch  needles, 
and  differing  also  in  the  length  of  the  main-plate,  which  in 
the  four-inch  compass  is  twelve  and  a half  inches  long,  and 
in  the  larger  sizes,  fifteen' and  a half  inches. 

The  six-inch  needle  compass  is  generally  preferred. 

Weight  of  the  Plain  Compasses. 

The  average  weights  of  the  different  sizes,  with  the  brass 
mountings  of  the  jacob-staff,  are : 

For  the  4-inch  needle,  5f  lbs. 

For  the  5-inch  “ 6^  “ 

For  the  6-inch  “ 8 “ 


POCKET  INSTRUMENTS 


THE  POCKET  SOLAR  COMPASS. 


Price,  with  Staff  Mountings $100 

“ “ Light  Tripod,  as  in  Fig.  33 105 

“ 44  Light  Extension  Tripod 110 

“ “ “ 44  44  and  Leveling  Plates  120 

“ of  Side  Telescope  and  Counterpoise  fitted  to  New  Pocket  Solar  Com- 
pass   25 

t*  of  Leather  Case  with  Shoulder  Strap  for  New  Pocket  Solar  Compass  5 


00 

00 

00 

00 

00 

00 


148 


POCKET  COMPASSES. 


We  manufacture  a variety  of  small  instruments  so  portable 
and  yet  so  efficient  that  they  are  often  used  in  preference 
to  the  larger  ones,  especially  for  preliminary  or  reconnoiter- 
ing  work,  and  these  will  now  be  described. 

The  Pocket  Solar  Compass,  well  shown  m Fig.  33, 
has  a needle  3 inches  long,  and  a limb  of  4J  inches  diameter, 
divided  to  half  degrees  and  reading  by  its  one  double  vernier 
horizontal  angles  to  single  minutes. 

The  arrangement  of  the  plates  is  similar  to  that  of  the 
large  Solar  Compass,  the  under  plate  carrying  the  sights 
revolving  around  the  upper  or  compass  plate,  to  which  are 
attached  the  solar  apparatus,  levels,  &c. ; there  is  also  a 
clamp  with  tangent-screw  between  the  two  plates,  and 
another  to  the  whole  instrument  about  its  spindle. 

The  distance  between  the  sights  is  nearly  7 inches,  the 
sights  themselves  are  4^  inches  high,  and  have  a slot  and 
hair  in  half  their  heights ; they  are  hinged  so  as  to  fold 
down  in  packing. 

The  compass-circle  is  arranged  with  pinion  and  movable 
part  so  as  to  set  off  the  variation  of  the  needle  to  five 
minutes  ; the  needle  has  a lifting-lever,  as  usual,  by  which 
it  is  raised  against  the  glass. 

The  solar  apparatus  is  attached  to  the  flange  of  the  upper 
plate,  and  consists  of  the  usual  hour , latitude , and  declina- 
tion arcs , marked  respectively  A C and  B in  the  cut,  with  ah 
arm,  FF,  to  the  last  named,  carrying  the  solar  lenses  and 
lines  as  in  the  larger  instruments.  The  latitude  and  declina- 
tion arcs  are  each  divided  to  half  degrees,  and  read  by 
verniers,  the  latitude  arc  to  five  minutes,  and  the  declina- 
tion arc  to  single  minutes  of  a degree  ; the  hour  arc  is 
divided  on  its  inner  edge  into  hours  and  twelfths,  or  spaces 
of  five  minutes  each,  the  index  of  the  declination  arc  above 
easily  enabling  one  to  read  the  time  to  single  minutes. 

The  hour  arc  is  made  movable  upon  its  supporting  seg- 


POCKET  COMPASSES. 


149 


ment  to  either  side,  its  outer  edge  being  also  divided  on  the 
middle  portion  to  spaces  of  five  minutes  of  time,  and  read 
by  a vernier  upon  the  segment  to  single  minutes  ; in  this  way 
the  equation  of  time  for  any  given  day  is  set  off  at  once,  and 
the  time  given  by  the  index  of  the  hour  arc  thus  made  to 
agree  with  mean  time  or  that  given  by  the  ordinary  clock. 

The  solar  lenses  and  lines  are  placed  as  in  the  larger 
instruments,  the  declination  arc  being  also  reversible,  as  the 
sun  changes  from  north  to  south  of  the  equator. 

When  packed  in  the  case  the  declination  arc  with  its  arm 
is  detached  from  the  hour  arc  ; and  this  itself,  together  with 
the  latitude  arc,  folds  closely  to  the  compass-box. 

The  Pocket  Solar  is  set  up  for  use  either  upon  a ball 
spindle,  with  staff  mountings,  or  as  in  Fig.  33,  upon  a light 
tripod  like  the  other  pocket  compasses,  and  often  with 
small  leveling-head  with  clamp  and  tangent  screws. 

Sometimes  a side  telescope  with  counterpoise  is  substi- 
tuted for  the  sight- vanes. 

To  Use  the  Pocket  Solar . 

The  instrument  is  set  upon  its  tripod  or  staff,  and  care- 
fully leveled;  the  declination  of  the  sun  for  the  given  day 
and  hour  is  obtained  from  the  Ephemeris  supplied  by  us 
with  this  and  other  solar  instruments,  and  set  off  upon  its 
arc,  and  the  hour  arc  is  raised  until  its  vernier  marks  the 
latitude  of  the  place  upon  the  latitude  arc. 

The  equation  of  time  for  the  day  is  also  set  off  as  before 
described,  the  zero  of  the  hour  circle  being  moved  to  the 
right  when  the  equation  is  to  be  added,  and  to  the  left  when 
it  is  to  be  subtracted  from  apparent  time. 

The  index  of  the  declination  arc  being  then  set  to  the 
proper  division  on  the  hour  arc,  and  the  declination  arm 
directed  to  the  sun,  the  limb  being  also  set  at  zero,  and  the 


150 


POCKET  COMPASSES. 


sun’s  image  brought  between  the  hour  lines  of  the  silver 
plate  by  turning  the  whole  instrument  upon  its  spindle, 
the  sights  will  indicate  the  true  meridian  precisely  as  with 
the  larger  Solar  Compass. 

The  compass-circle  being  now  turned  by  the  pinion  until 
the  needle  points  to  zero,  the  needle  also  will  be  set  to  the 
true  meridian,  and  the  variation  of  the  needle  can  be  read 
off  upon  the  outside  divisions  of  the  compass-box. 

The  Adjustments  and  use  of  this  Pocket  Solar  are 
substantially  the  same  as  those  of  the  Solar  Compass  already 
described,  and  its  indications  so  accurate  that  after  repeated 
trials  we  are  satisfied  that  it  will  give  the  true  meridian 
within  an  error  of  less  than  three  minutes  of  a degree,  which 
taken  in  connection  with  the  deflection  of  the  magnetic 
needle  will  indicate  with  certainty  the  presence  and  direc- 
tion of  veins  of  magnetic  iron  ore. 

Indeed  we  have  the  assurance  of  competent  surveyors  that 
while  it  is  much  more  portable  it  is  also  very  nearly  or  quite 
as  accurate  in  all  its  indications  as  the  large  Solar  Com- 
pass ; its  weight,  excluding  box  and  tripod,  is  4J  lbs. 


POCKET  COMPASSES. 


151 


POCKET  RAILROAD  COMPASS. 


Fig.  34. 


Price  as  shown,  with  tripod,  $45.00. 

This  instrument  is  a single  vernier  Railroad  Compass  in 
miniature,  the  arrangement  of  the  plates  being  in  appear- 
ance very  similar  to  those  of  the  Pocket  Solar  just  described, 
except  that  the  compass-circle  with  levels,  sights,  &c.,  is 
now  on  the  upper  or  main  plate. 

The  limb  is  on  the  lower  plate,  is  five  inches  in  diameter, 
and  reads  to  single  minutes  by  the  vernier.  The  needle  is 
3\  inches  long,  and  its  variation  can  be  set  off  to  single 
minutes  as  in  the  larger  instruments. 

The  Pocket  Railroad  Compass  can  be  used  for  a great 
variety  of  work,  and  with  light  extension  tripod  is  especially 


152 


POCKET  COMPASSES. 


adapted  for  surveys  of  mines,  &c.,  where  angles  must  be 
taken  independently  of  the  needle. 

The  price  of  this  little  instrument  which  we  have  just 
now  introduced  with  staff  mountings  only  will  be  $40,  with 
light  tripod  $45,  and  if  with  extension  tripod  $50. 

Another  and  more  common  form  of  this  instrument  is 
shown  in  Fig.  35,  with  attachments  of  telescope,  etc. 

In  this  style  of  the  Pocket  Railroad  Compass  the  plates 
are  circular,  the  sights  being  screwed  to  the  lower  one,  the 
compass-circle  above,  and  turning  around  the  lower  plate  to 
set  off  the  variation  of  the  needle. 

The  limb  is  underneath  the  compass-face,  but  not  shown 
in  the  cut,  and  read  by  one  double  vernier  under  the  glass 
to  five  minutes  of  a degree  in  the  3^-inch  needle  instru- 
ment, and  to  single  minutes  in  the  one  with  4^-inch  needle; 
the  last-named  has  also  a clamp  and  tangent  to  the  limb, 
the  3^-inch  size  a clamp-screw  only. 

A clamp  and  tangent  movement  to  the  spindle  is  added 
whenever  desired,  and  at  small  additional  cost. 

The  sights  are  made  to  fold  down  closely  to  the  glass  for 
convenience  in  packing;  they  are  each  made  half-slot,  and 
half-hair,  so  as  to  take  back  and  fore  sights  without  turning 
the  instrument. 

Telescopic  Attachments. 

To  the  compasses  with  4^-inch  needles  we  have  recently 
adapted  a telescopic  attachment  as  in  Fig.  35.  When  the 
sights  are  raised  upright,  a cross-piece  is  fastened  by  milled- 
head  screws  to  their  tops,  and  thus  a telescope  placed  in 
position,  making  the  instrument  in  effect  a very  light  Sur- 
veyors’ Transit. 

The  attachments  of  a vertical  circle,  level,  and  clamp  and 
tangent  as  shown  in  the  figure,  can  also  be  added,  and  thus  the 
means  furnished  for  taking  grades  and  running  levels  with 
accuracy  sufficient  for  the  common  practice  of  the  surveyor. 


POCKET  COMPASSES. 


153 


Fig.  85. 


PRICES. 

Railroad  Pocket  Compass,  4^-inch  needle,  clamp  and  tangent  to  limb,  with 


limb  reading  to  one  minute,  with  jacob-staff  mountings $28  00 

Tripod  for  Pocket  Compass 5 00 

Clamp  and  Tangent  Movement  to  ball  spindle 5 00 

Telescope  No.  131,  with  vertical  circle,  level  on  telescope  and  clamp  and 

tangent  to  telescope  axis 32  00 

Or  complete,  as  shown  in  Fig.  35 70  00 

“ “ “ and  with  stadia  wires 73  00 


154 


POCKET  COMPASSES. 


When  the  telescope  is  applied,  the  sights  are  now  placed 
by  us  to  one  side  of  the  line  of  zeros,  and  the  telescope  is 
then  brought  into  that  line,  and  over  the  centre  of  the  in- 
strument. 

The  cross-piece  with  telescope  is  detached  when  the 
Pocket  Compass  is  put  into  its  case,  and  replaced  in  a few 
moments  time,  and  without  derangement  of  any  adjust- 
ments. 

The  Pocket  Eailroad  Compass  can  be  used  either  on  a 
jacob-staff,  or  with  small  tripod,  as  in  Fig.  35,  and  if 
desired,  with  small  leveling  head. 

THE  VERNIER  POCKET  COMPASS.  (Fig.  86.) 

This  is  a most  excellent  and  portable  instrument  for 
preliminary  work,  having  a line  needle,  and  also  a vernier 
and  clamping-nut  by  which  the  sights  can  be  placed  at  an 
angle  with  the  line  of  zeros,  so  as  to  set  off  the  variation 
of  the  needle,  as  with  the  Vernier  Compass. 

The  sights  are  made  with  a slot  in  the  south  vane,  and  a 
hair  in  the  north  one,  for  readily  finding  the  object ; they 
also  fold  down  to  the  compass,  when  it  is  packed  in  the 
case. 

The  compass  is  furnished  with  jacob-staff  mountings; 
often  a very  light  tripod  is  ordered  for  it ; it  has  also  two 
levels,  and  is  neatly  packed  in  a mahogany  case. 

We  make  two  sizes  of  the  Vernier  Pocket  Compass  hav- 
ing needles  of  3^  and  4^  inches  respectively  ; the  smaller 
size  has  the  compass-circle  divided  to  single  degrees,  and 
the  variation  vernier  reads  to  five  minutes;  in  the  4^-inch 
size,  the  circle  is  divided  to  half-degrees,  and  the  variation 
set  off  to  single  minutes.  When  desired,  a rack-movement 
with  pinion  is  supplied,  in  order  to  set  off  the  variation 


POCKET  COMPASSES. 


155 


more  readily.  (See  “.Pocket  Compasses  and  Extras,”  in 
Price  List.) 


Fig.  36. 


Price  as  shown,  3|-inch  needle,  with  tripod,  $21.00. 
If  4|-inch  needle,  and  tripod,  23.00. 


156 


POCKET  COMPASSES. 


TELESCOPIC  ATTACHMENT,  ETC. 


Fig.  37 

Price,  complete  as  shown,  $60.00. 
(See  Price  List  No.  161.) 


Fig.  37  shows  the  arrangement  for  attaching  to  the  sights 
of  the  4^-inch  Vernier  Pocket  Compass  a telescope  and 
extras,  making  this  little  instrument  a Transit  Compass  for 


POCKET  COMPASSES. 


157 


ordinary  land  surveying  and  reconnoissance,  with  power  to 
give  levels  and  grades  with  accuracy  sufficient  for  all  ordi- 
nary practice. 

The  sights  in  such  an  arrangement  are  placed  at  one 
side,  that  the  telescope  may  be  directly  over  the  centre, 
and  in  such  case  the  instrument  should  have  a clamp  and 
tangent  movement  for  spindle,  as  shown  in  the  figure. 

When  packed  for  transportation,  the  telescope  and  cross- 
piece are  detached  from  the  sights,  and  packed  separately 
in  the  case. 

Staff  Mountings  are  always  furnished  with  these 
compasses;  and  a light  tripod,  as  shown  in  Fig.  37,  is  very 
generally  added. 

THE  PLAIN  POCKET  COMPASS. 


Fig.  38. 


See  Price  List  Nos.  150  to  154. 

Besides  the  Vernier  Pocket  Compass  we  also  furnish  an 
instrument  without  a vernier,  but  often  a very  serviceable 
compass. 

These  are  made  of  2J  or  3^-inch  needles  in  the  different 
sizes,  and  supplied  with  levels  and  jacob-staff  mountings  as 
desired;  they  are  also  packed  in  a light  mahogany  case,  the 
sights  folding  down  close  to  the  glass. 


158 


SOCKET  COMPASSES. 


MINERS’  OR  DIP  COMPASSES. 


The  Dip  Compasses,  two  forms  of  which  are  shown  in 
figures  39  and  40,  consist  essentially  of  a magnetic-needle 
so  suspended  as  to  move  readily  in  a vertical  direction,  the 
angle  of  inclination  or  “dip”  being  measured  upon  the 
divided  rim  of  a small  compass-box. 

When  in  use,  the  ring  or  bail  is  held  in  the  hand — the 
compass-box  by  its  own  weight  takes  a vertical  position — 
and  must  also  be  in  the  plane  of  the  magnetic  meridian. 

In  this  position  the  needle,  when  unaffected  by  the 


POCKET  COMPASSES. 


159 


attraction  of  iron,  assumes  a horizontal  line,  as  shown  by 
the  zeros  of  the  circle.  When  brought  oyer  any  mass  of 
iron  it  dips,  and  thus  detects  the  presence  of  iron  ores  with 
certainty. 

If  the  Miners’  Compass  is  held  horizontally  it  serves  as 
an  ordinary  Pocket  Compass,  and  indicates  the  magnetic 
meridian,  in  the  plane  of  which  it  should  be  held  when  used 
to  ascertain  the  dip  of  the  place  where  the  observation  is 
made. 

Several  different  styles  of  this  instrument  are  made; 
that  shown  in  Fig.  39,  with  a 3-inch  needle,  has  the  two 
sides  of  glass,  and  is  provided  when  desired  with  a stop  for 
the  needle,  worked  by  the  little  brass  knob  between  the  ends 
of  the  ring. 

Another  form  has  a brass  back  with  cover  of  the  same 
material  and  a needle  of  2^  inches. 

The  Norwegian  Compass , Fig.  40,  is  a modifica- 
tion of  one  used  in  Northern  Europe. 

This  has  a needle  of  either  3 or  4 inches  resting  upon  a 
single  vertical  pivot  so  as  to  move  freely  in  a horizontal 
direction,  and  thus  place  itself  with  certainty  in  the  magnetic 
meridian  ; while  at  the  same  time,  being  attached  to  the 
needle-cap  by  two  delicate  pivots,  one  on  each  side,  it  is  free 
to  dip — like  that  of  the  ordinary  miners’  compass,  described 
above. 

The  Norwegian  Compass  is  usually  provided  with  brass 
covers  on  both  sides ; Fig.  39  is  packed  in  a light  mahogany 
box. 


160 


POCKET  COMPASSES. 


THE  DIAL  COMPASS. 


Fig.  41.  Price,  $16.00. 


This  little  instrument  has  a needle  three  inches  long,  and 
with  its  compass  circle  is  inclosed  in  a circular  box  set  upon 
a brass  base  four  inches  square,  three  edges  of  which  are 
chamfered  and  divided;  one  on  the  W-side  of  the  compass 
into  inches  and  tenths,  the  two  others  into  degrees  and  half 
degrees,  and  figured  from  a centre  on  the  southwest  corner 
of  the  base. 

The  compass  circle  is  movable  in  order  to  set  off  the 
variation  of  the  needle,  and  has  a vernier  attached  to  it  on 
the  inside,  reading  a divided  arc  on  the  face  of  the  compass 
to  three  minutes  of  a degree. 

There  is  also  on  the  south  side  of  the  face  an  arc  of  180°, 


POCKET  COMPASSES. 


161 


figured  from  0 to  90  on  each  side  of  the  south  or  zero  line 
of  the  face. 

A little  pendulum  with  index  point  hung  from  the  center- 
pin  reads  this  arc,  when  the  compass  is  set  up,  vertical,  on 
the  raised  south  edge,  thus  making  it  a clinometer  or  slope 
measurer. 

The  sight  is  hinged  so  as  to  fold  in  packing,  but  when 
erect,  makes  taut  a fine  silk  thread  attached  at  one  end  to 
the  sight  and  at  the  other  to  a brass  hour-circle  above  the 
compass  glass,  at  an  angle  with  the  plane  of  the  hour-circle 
equal  to  that  of  the  latitude  of  the  place  where  the  compass 
is  used.  The  hour-circle  is  divided  for  any  required  latitude 
like  that  of  a sun-dial,  the  hair  serving  as  a gnomon  to  give 
apparent  time  with  the  sun. 

When  it  is  desired  to  use  the  instrument  at  a latitude  a 
degree  or  two  either  higher  or  lower  than  that  for  which  the 
hour-circle  is  divided,  the  end  of  the  thread  attached  to  the 
sight  may  be  made  adjustable,  so  as  to  be  either  raised  or 
lowered  on  the  sight  until  the  angle  of  the  thread  with  the 
plane  of  the  hour-circle  is  made 'equal  to  that  of  the  latitude 
required. 

In  using  the  Dial  Compass  it  is  first  leveled  carefully,  the 
equation  of  time  for  the  given  day  allowed  for,  and  then  by 
observation  on  the  sun  at  midday  the  true  meridian  approx- 
imately obtained. 

The  needle  may  then  be  set  to  the  meridian  by  laying  off 
the  variation,  and  any  deflection  of  the  needle  from  the 
true  meridian  will  indicate  the  presence  of  veins  of  magnetic 
iron  ore.  Its  use  as  a clinometer  has  been  already  described. 


162 


LEVELING  INSTRUMENTS. 


LEVELING  INSTRUMENTS. 

THE  Y LEVEL. 

Of  the  different  varieties  of  the  leveling  instrument,  that 
termed  the  Y Level  has  been  almost  universally  preferred 
by  American  engineers,  on  account  of  the  facility  of  its 
adjustment  and  superior  accuracy. 

Of  these  levels  we  manufacture  four  different  sizes,  having 
telescopes  of  fifteen,  eighteen,  twenty,  and  twenty-two  inches 
long,  respectively. 

The  engraving,  Fig.  42,  represents  our  twenty-inch  Y 
Level. 

We  shall  consider  the  several  parts  of  the  instrument  in 
detail: 

The  telescope  has  at  each  end  a ring  of  bell-metal, 
turned  very  truly  and  both  of  exactly  the  same  diameter; 
by  these  it  revolves  in  the  wyes,  or  can  be  at  pleasure 
clamped  in  any  position  when  the  clips  of  the  wyes  are 
brought  down  upon  the  rings,  by  pushing  in  the  tapering- 
pins. 

The  telescope  has  a rack  and  pinion  movement  to  both 
object-glass  and  eye-piece,  an  adjustment  for  centering  the 
eye-piece,  shown  at  A A,  in  the  sectional  view  of  the  instru- 
ment (Eig.  43),  and  another  seen  at  C,  for  ensuring  the 
accurate  projection  of  the  object-glass,  in  a straight  line. 

Both  of  these  are  completely  concealed  from  observation 
and  disturbance  by  thin  rings  which  screw  over  them. 

The  telescope  has.  also  a shade  over  the  object-glass,  so 
made  that,  whilst  it  may  be  readily  moved  on  its  slide  over 
the  glass,  it  cannot  be  dropped  off  and  lost. 

A small  compass,  without  sights  and  with  2^-inch  needle, 
is  sometimes  attached  to  the  telescopes  of  the  larger  level- 
ing instruments,  and  used  to  obtain  the  bearing  of  lines 
when  desired ; its  extra  cost  is  $10.00. 


20-INCH  Y LEVEL. 


164 


LEVELING  INSTRUMENTS. 


The  interior  construction  of  the  telescope  will  be  readily 
understood  from  Fig.  43,  which,  exhibits  the  adjustment  which 
insures  the  accurate  projection  of  the  object-glass  slide. 

As  this  is  peculiar  to  our  instruments,  and  is  always 
made  by  the  maker  so  permanently  as  to  need  no  further 
attention  at  the  hands  of  the  engineer,  we  shall  here 
describe  the  means  by  which  it  is  effected,  somewhat  in 
detail. 

The  necessity  for  such  an  adjustment  will  appear,  when 
we  state,  that  it  is  almost  impossible  to  make  a telescope 
tube  perfectly  straight  on  its  interior  surface. 

Such  being  the  case,  it  is  evident  that  the  object-glass 
slide  which  is  fitted  to  this  surface,  and  moves  in  it,  must 
partake  of  its  irregularity,  so  that  the  glass  and  the  line  of 
collimation  depending  upon  it,  though  adjusted  in  one  posi- 
tion of  the  slide,  will  be  thrown  out  when  the  slide  is  moved 
to  a different  point. 

To  prove  this,  let  any  level  be  selected  which  is  con- 
structed in  the  usual  manner,  and  the  line  of  collimation 
adjustment  upon  an  object  taken  as  near  as  the  range  of 
the  slide  will  allow ; then  let  another  be  selected,  as  distant 
as  may  be  clearly  seen  ; upon  this  revolve  the  wires,  and 
they  will  almost  invariably  be  found  out  of  adjustment, 
sometimes  to  an  amount  fatal  to  any  confidence  in  the 
accuracy  of  the  instrument.  The  arrangement  adopted  by 
us  to  correct  this  imperfection,  and  which  so  perfectly 
accomplishes  its  purpose,  is  shown  in  Fig.  43. 

Here  are  seen  the  two  bearings  of  the  object-glass  slide, 
one  being  in  the  narrow  bell* metal  ring,  which  slightly 
contracts  the  diameter  of  the  main  tube,  the  other  in  the 
small  adjustable  ring,  also  of  bell-metal,  shown  at  0,  and 
suspended  by  four  screws  in  the  middle  of  the  tele- 
scope. 

Advantage  is  here  taken  of  the  fact,  that  the  rays  of 


LEVELING  INSTRUMENTS. 


165 


Fig.  43. 


166 


LEVELING  INSTRUMENTS. 


light  are  converged  by  the  object-glass,  so  that  none  are 
obstructed  by  the  contraction  of  the  slide,  except  those 
which  diverge,  and  which  ought  always  to  be  intercepted, 
and  absorbed  in  the  blackened  surface  of  the  interior  of  the 
slide. 

Now,  in  such  a telescope,  the  perfection  of  movement  of 
the  slide, depends  entirely  upon  its  exterior  surfaces,  at  the 
points  of  the  two  bearings. 

These  surfaces  are  easily  and  accurately  turned,  concen- 
tric, and  parallel  with  each  other,  and  being  fitted  to  the 
rings,  it  only  remains  necessary  to  adjust  the  position  of  the 
smaller  ring,  so  that  its  centre  will  coincide  with  that  of  the 
optical  axis  of  the  object-glass. 

When  this  has  been  once  well  done,  no  further  correction 
will  be  necessary,  unless  the  telescope  should  be  seriously 
injured. 

The  manner  in  which  the  adjustment  of  the  object-glass 
slide  is  effected,  will  be  considered  when  we  come  to  speak 
of  the  other  adjustments. 

Rach  and  Pinion . — As  seen  in  the  engraving,  our 
Level  telescopes  are  usually  furnished  with  the  ordi- 
nary rack  and  pinion  movement  to  both  object  and  eye 
tubes. 

The  advantages  of  an  eye-piece  pinion  are,  that  the  eye- 
piece can  be  shifted  without  danger  of  disturbing  the  tele- 
scope, and  that  the  wires  are  more  certainly  brought  into 
distinct  view,  so  as  to  avoid  effectually  any  error  of  obser- 
vation, arising  from  what  is  termed  the  instrumental 
parallax. 

We  usually  place  our  object-slide  pinion  on  the  side — 
both  of  Transit  telescopes,  and  of  those  of  the  Level.  The 
pinion  of  the  eye-tube  is  always  placed  on  the  side  of  the 
telescope. 

The  Level  or  ground  bubble  tube  is  attached  to  the 


LEVELING  INSTRUMENTS. 


167 


under  side  of  the  telescope,  and  furnished  at  the  different 
ends  with  the  usual  movements,  in  both  horizontal  and 
vertical  directions. 

The  aperture  of  the  tube,  through  which  the  glass  vial 
appears,  is  about  five  and  one-fourth  inches  long,  being 
crossed  at  the  centre  by  a small  rib  or  bridge,  which  greatly 
strengthens  the  tube. 

The  level  scale  which  extends  over  the  whole  length,  is 
graduated  into  tenths  of  an  inch,  and  figured  at  every  fifth 
division,  counting  from  zero  at  the  centre  of  the  bridge  ; 
the  scale  is  set  close  to  the  glass. 

The  level  vial  is  made  of  thick  glass  tube,  selected  so 
as  to  have  an  even  bore  from  end  to  end,  and  finely  ground 
on  its  upper  interior  surface,  that  the  run  of  the  air-bubble 
may  be  uniform  throughout  its  whole  range. 

The  sensitiveness  of  a ground  level,  is  determined  best  by 
an  instrument  called  a level-tester,  having  at  one  end  two 
Y’s  to  hold  the  tube,  and  at  the  other  a micrometer  wheel 
divided  into  hundredths,  and  attached  to  the  top  of  a fine- 
threaded  screw  which  raises  the  end  of  the  tester  very 
gradually. 

The  number  of  divisions  passed  over  on  the  perimeter  of 
the  wheel,  in  carrying  the  bubble  over  a tenth  of  the  scale, 
is  the  index  of  the  delicacy  of  the  level.  In  the  tester  which 
we  use,  a movement  of  the  wheel  ten  divisions  to  one  of  the 
scale,  indicates  the  degree  of  delicacy  generally  preferred 
for  railroad  engineering. 

For  canal  work  practice,  a more  sensitive  bubble  is  often 
desired,  as,  for  instance,  one  of  seven  or  eight  divisions  of 
the  wheel,  to  one  of  the  scale. 

The  Wyes  of  our  levels  are  made  large  and  strong,  of 
the  best  bell-metal,  and  each  have  two  nuts,  both  being 
adjustable  with  the  ordinary  steel  pin. 

The  clips  are  brought  down  on  the  rings  of  the  telescope- 


168 


LEVELING  INSTRUMENTS. 


tube  by  the  Y pins,  which  are  made  tapering,  so  as  to  clamp 
the  rings  very  firmly. 

The  clip  of  one  of  the  wyes  has  a little  pin  projecting 
from  it,  which  entering  a recess  filed  in  the  edge  of  the 
ring,  ensures  the  vertical  position  of  the  level  and  cross- 
wire. 

The  Level-Bar  is  made  round,  of  the  best  bell-metal, 
and  shaped  so  as  to  possess  the  greatest  strength  in  the 
parts  most  subject  to  sudden  strains. 

Connected  with  the  level-bar  is  the  head  of  the  tripod- 
socket. 

The  Tripod- Socket  is  compound  ; the  interior  spin- 
dle D,  Fig.  43,  upon  which  the  whole  instrument  is  sup- 
ported, is  made  of  steel,  and  nicely  ground,  so  as  to  turn 
evenly  and  firmly  in  a hollow  cylinder  of  bell-metal ; this 
again  has  its  exterior  surface  fitted  and  ground  fo  the  main 
socket  E E of  the  tripod-head. 

The  bronze  cylinder  is  held  upon  the  spindle  by  a washer 
and  screw,  the  head  of  the  last  having  a hole  in  its  centre, 
through  which  the  string  of  the  plumb-bob  is  passed. 

The  upper  part  of  the  instrument,  with  the  socket,  may 
thus  be  detached  from  the  tripod-head ; and  this  also,  as  in 
the  case  of  all  our  instruments,  can  be  unscrewed  from  the 
legs,  so  that  both  may  be  conveniently  packed  in  the  box. 

A little  under  the  upper  parallel  plate  of  the  tripod-head, 
and  in  the  main  socket,  is  a screw  which  can  be  moved  into 
a corresponding  groove,  turned  on  the  outside  of  the  hollow 
cylinder,  and  thus  made  to  hold  the  instrument  in  the 
tripod  when  it  is  carried  upon  the  shoulders. 

It  will  be  seen  from  the  engraving,  that  the  arrangement 
just  described  allows  long  sockets,  and  yet  brings  the  whole 
instrument  down  as  closely  as  possible  to  the  tripod-head, 
both  objects  of  great  importance  in  the  construction  of  any 
instrument. 


LEVELING  INSTRUMENTS. 


169 


The  Leveling  Head  has  the  same  plates  and  level- 
ing-screws as  that  described  in  the  account  of  the  En- 
gineers’ Transit ; the  tangent-screw,  however,  is  commonly 
single. 

For  our  fifteen-inch  level  we  make  a tripod-head, 
similar  to  that  used  with  the  lighter  Engineers’  Transit. 

The  Adjustments . 

Having  now  completed  the  description  of  the  different 
parts  of  the  Leveling  Instrument,  we  are  ready  to  proceed 
with  their  adjustments,  and  shall  begin  with  that  of  the 
object-slide,  which,  although  always  made  by  the  maker,  so 
permanently  as  to  need  no  further  attention  at  the  hands 
of  the  engineer,  unless  in  cases  of  derangement  by  acci- 
dent, is  yet  peculiar  to  our  instruments,  and  therefore  not 
familiar  to  all  engineers. 

To  Adjust  the  Object-Slide . — The  maker  selects 
an  object  as  distant  as  may  be  distinctly  observed,  and 
upon  it  adjusts  the  line  of  collimation,  in  the  manner  here- 
after described,  making  the  centre  of  the  wires  to  revolve 
without  passing  either  above  or  below  the  point  or  line 
assumed. 

In  this  position,  the  slide  will  be  drawn  in  nearly  as  far 
as  the  telescope-tube  will  allow. 

He  then,  with  the  pinion-head,  moves  out  the  slide  until 
an  object,  distant  about  ten  or  fifteen  feet,  is  brought 
clearly  into  view  ; again  revolving  the  telescope  in  the  Y’s, 
he  observes  whether  the  wires  will  reverse  upon  this  second 
object. 

Should  this  happen  to  be  the  case,  he  will  assume  that, 
as  the  line  of  collimation  is  in  adjustment  for  these  two 
distances,  it  will  be  so  for  all  intermediate  ones,  since  the 


170 


LEVELING  INSTRUMENTS. 


bearings  of  the  slide  are  supposed  to  be  true,  and  their 
planes  parallel  with  each  other. 

If,  however,  as  is  most  probable,  either  or  both  wires  fail 
to  reverse  upon  the  second  point,  he  must  then,  by  estima- 
tion, remove  half  the  error  by  the  screws  at  C (Fig  43), at 
right  angles  to  the  hair  sought  to  be  corrected,  remembering, 
at  the  same  time,  that  on  account  of  the  inverting  property 
of  the  eye-piece,  he  must  move  the  slide  in  the  direction 
which  apparently  increases  the  error.  When  both  wires 
have  thus  been  treated  in  succession,  the  line  of  collimation 
is  adjusted  on  the  near  object,  and  the  telescope  again 
brought  upon  the  most  distant  point ; here  the  tube  is 
again  revolved,  the  reversion  of  the  wires  upon  the  object 
once  more  tested,  and  the  correction,  if  necessary,  made  in 
precisely  the  same  manner. 

He  proceeds  thus,  until  the  wires  will  reverse  upon  both 
objects  in  succession ; the  line  of  collimation  will  then  be 
in  adjustment  at  these  and  all  intermediate  points,  and  by 
bringing  the  screw-heads,  in  the  course  of  the  operation,  to 
a firm  bearing  upon  the  washers  beneath  them,  the  adjust- 
able ring  will  be  fastened  so  as  for  maoy  years  to  need  no 
further  adjustment. 

When  this  has  been  completed,  the  thin  brass  ferule  is 
screwed  over  the  outside  ring,  concealing  the  screw-heads, 
and  avoiding  the  danger  of  their  disturbance  by  an  inexpe- 
rienced operator. 

In  effecting  this  adjustment,  it  is  always  best  to  bring  the 
wires  into  the  centre  of  the  field  of  view,  by  moving  the  lit- 
tle screws  A A (Fig.  43),  working  in  the  ring  which  em- 
braces the  eye-piece  tube. 

Should  the  engineer  desire  to  make  the  adjustment  of  the 
object-slide,  it  will  be  necessary  to  remove  the  bubble-tube, 
in  order  that  the  small  screw  immediately  above  its  scale 
may  be  operated  upon  with  the  screw-driver. 


LEVELING  INSTRUMENTS. 


171 


The  adjustment  we  have  now  given  is  preparatory  to 
those  which  follow,  and  are  common  to  all  leveling  instru- 
ments of  recent  construction,  and  are  all  that  the  engineer 
will  have  to  do  with  in  using  our  own  instruments.  What 
is  still  necessary  then  is — 

1.  To  adjust  the  line  of  collimation , or  in  other  words,  to 
bring  both  wires  into  the  optical  axis,  so  that  their  point  of 
intersection  will  remain  on  any  given  point,  during  an  en- 
tire revolution  of  the  telescope. 

2.  To  bring  the  level-bubble  parallel  with  the  bearings  of 
the  Y rings,  and  with  the  longitudinal  axis  of  the  tele- 
scope. 

3.  To  adjust  the  wyes , or  to  bring  the  bubble  into  a 
position  at  right  angles  to  the  vertical  axis  of  the  instru- 
ment. 

To  Adjust  the  Line  of  Collimation « set  the  tri- 
pod firmly,  remove  the  Y pins  from  the  clips,  so  as  to 
allow  the  telescope  to  turn  freely,  clamp  the  instrument  to 
the  tripod-head,  and,  by  the  leveling  and  tangent-screws, 
bring  either  of  the  wires  upon  a clearly  marked  edge  of 
some  object,  distant  from  one  hundred  to  five  hundred  feet. 

Then  with  the  hand  carefully  turn  the  telescope  half- 
way around,  so  that  the  same  wire  is  compared  with  the 
object  assumed. 

Should  it  be  found  above  or  below,  bring  it  half-way  back 
by  moving  the  capstan-head  screws  at  right  angles  to  it, 
remembering  always  the  inverting  property  of  the  eye- 
piece ; now  bring  the  wire  again  upon  the  object,  and  re- 
peat the  first  operation  until  it  will  reverse  correctly. 

Proceed  in  the  same  manner  with  the  other  wire  until 
the  adjustment  is  completed. 

Should  both  wires  be  much  out,  it  will  be  well  to  bring 
them  nearly  correct  before  either  is  entirely  adjusted. 

When  this  is  effected,  unscrew  the  covering  of  the  eye- 


m 


leveling  instruments. 


piece  centering  screws,  shown  in  the  sectional  view  (Fig.  43) 
at  A A,  and  move  each  pair  in  succession  with  a small 
screw-driver,  until  the  wires  are  brought  into  the  centre  of 
the  field  of  view. 

The  inverting  property  of  the  eye-piece  does  not  affect 
this  operation,  and  the  screws  are  moved  direct. 

To  test  the  correctness  of  the  centering,  revolve  the 
telescope,  and  observe  whether  it  appears  to  shift  the  posi- 
tion of  an  object. 

Should  any  movement  be  perceived,  the  centering  is  not 
perfectly  effected. 

It  may  here  be  repeated,  that  in  all  telescopes  the  posi- 
tion and  adjustment  of  the  line  of  collimation  depends  upon 
that  of  the  object-glass;  and,  therefore,  that  the  movement 
of  the  eye-piece  does  not  affect  the  adjustment  of  the  wires 
in  any  respect. 

When  the  centering  has  been  once  effected,  it  remains 
permanent,  the  cover  being  screwed  on  again  to  conceal  and 
protect  it  from  derangement  at  the  hands  of  the  curious  or 
inexperienced  operator. 

To  Adjust  the  Level-Bubble. — Clamp  the  instru- 
ment over  either  pair  of  leveling-screws,  and  bring  the  bub- 
ble into  the  centre  of  the  tube. 

Now  turn  the  telescope  in  the  wyes,  so  as  to  bring  the 
level-tube  on  either  side  of  the  centre  of  the  bar.  Should 
the  bubble  run  to  the  end,  it  would  show  that  the  vertical 
plane,  passing  through  the  centre  of  the  bubble,  was  not 
parallel  to  that  drawn  through  the  axis  of  the  telescope 
rings. 

To  correct  the  error,  bring  the  bubble  entirely  back, 
with  the  capstan-head  screws,  which  are  set  in  either  side 
of  the  level-holder,  placed  usually  at  the  object  end  of  the 
tube. 

Again  bring  the  level-tube  over  the  centre  of  the  bar, 


LEVELING  INSTRUMENTS. 


173 


and  the  bubble  to  the  centre,  turn  the  level  to  either 
side,  and,  if  necessary,  repeat  the  correction  until  the  bub- 
ble will  keep  its  position,  when  the  tube  is  turned  half  an 
inch  or  more,  to  either  side  of  the  centre  of  the  bar. 

The  necessity  for  this  operation  arises  from  the  fact,  that 
when  the  telescope  is  reversed  end  for  end  in  the  wyes  in 
the  other  and  principal  adjustment  of  the  bubble,  we  are 
not  certain  of  placing  the  level-tube  in  the  same  vertical 
plane;  and  therefore  it  would  be  almost  impossible  to 
effect  the  adjustment  without  a lateral  correction. 

Having  now,  in  great  measure,  removed  the  preparatory 
difficulties,  we  proceed  to  make  the  level-tube  parallel  with 
the  bearings  of  the  Y rings. 

To  do  this,  bring  the  bubble  into  the  centre  with  the 
leveling-screws,  and  then,  without  jarring  the  instrument, 
take  the  telescope  out  of  the  wyes  and  reverse  it  end  for 
end.  Should  the  bubble  run  to  either  end,  lower  that  end, 
or  what  is  equivalent,  raise  the  other  by  turning  the  small 
adjusting  nuts,  on  one  end  of  the  level,  until  by  estima- 
tion half  the  correction  is  made  ; again  bring  the  bubble 
into  the  centre  and  repeat  the  whole  operation,  until  the 
reversion  can  be  made  without  causing  any  change  in  the 
bubble. 

It  would  be  well  to  test  the  lateral  adjustment,  and  make 
such  correction  as  may  be  necessary  in  that,  before  the 
horizontal  adjustment  is  entirely  completed. 

To  Adjust  the  Wyes . — Having  effected  the  previous 
adjustments,  it  remains  now  to  describe  that  of  the  wyes,  or, 
more  precisely,  that  which  brings  the  level  into  position 
at  right  angles  to  the  vertical  axis,  so  that  the  bubble  will 
remain  in  the  centre  during  an  entire  revolution  of  the 
instrument. 

To  do  this,  bring  the  level-tube  directly  over  the  centre 
of  the  bar,  and  clamp  the  telescope  firmly  in  the  wyes, 


m 


LEVELING  INSTRUMENTS. 


placing  it  as  before,  over  two  of  the  leveling-screws,  un- 
clamp the  socket,  level  the  bubble,  and  turn  the  instru- 
ment half-way  around,  so  that  the  level-bar  may  occupy 
the  same  position  with  respect  to  the  leveling-screws 
beneath. 

Should  the  bubble  run  to  either  end,  bring  it  half-way 
back  by  the  Y nuts  on  either  end  of  the  bar;  now  move  the 
telescope  over  the  other  set  of  leveling-screws,  bring  the 
bubble  again  into  the  centre,  and  proceed  precisely  as  above 
described,  changing  to  each  pair  of  screws,  successively, 
until  the  adjustment  is  very  nearly  perfected,  when  it  may 
be  completed  over  a single  pair. 

The  object  of  this  approximate  adjustment,  is  to  bring  the 
upper  parallel  plate  of  the  tripod-head  into  a position  as 
nearly  horizontal  as  possible,  in  order  that  no  essential 
error  may  arise,  in  case  the  level,  when  reversed,  is  not 
brought  precisely  to  its  former  situation.  When  the  level 
has  been  thus  completely  adjusted,  if  the  instrument  is 
properly  made,  and  the  sockets  well  fitted  to  each  other 
and  the  tripod-head,  the  bubble  will  reverse  over  each  pair 
of  screws  in  any  position. 

Should  the  engineer  be  unable  to  make  it  perform  cor- 
rectly, he  should  examine  the  outside  socket  carefully  to 
see  that  it  sets  securely  in  the  main  socket,  and  also 
notice  that  the  clamp  does  not  bear  upon  the  ring  which 
it  encircles. 

When  these  are  correct,  and  the  error  is  still  manifested, 
it  will,  probably,  be  in  the  imperfection  of  the  interior 
spindle. 

After  the  adjustments  of  the  level  have  been  effected,  and 
the  bubble  remains  in  the  centre,  in  any  position  of  the 
socket,  the  engineer  should  turn  the  telescope  in  the  wyes 
until  the  pin  on  the  clip  of  the  wye  will  enter  the  little 
recess  in  the  ring  to  which  it  is  fitted,  and  by  which  is 


LEVELING  INSTRUMENTS. 


175 


ensured  the  vertical  position  of  the  spirit-level  and  cross- 
wire. 

When  the  pin  is  in  its  place  the  vertical-wire  may  be 
applied  to  the  edge  of  a building,  and  in  case  it  should  not 
be  parallel  with  it  two  of  the  cross-wire  screws  that  are  at 
right  angles  to  each  other  may  be  loosened,  and  by  the 
screws  outside,  the  cross-wire  ring  turned  until  the  wire  is 
vertical ; the  line  of  collimation  must  then  be  corrected 
again  and  the  adjustments  of  the  level  will  be  complete. 

To  Use  the  Level . 

When  using  the  instrument,  the  legs  must  be  set  firmly 
into  the  ground,  and  neither  the  hands  nor  person  of  the 
operator  be  allowed  to  touch  them  ; the  bubble  should  then 
be  brought  over  each  pair  of  leveling-screws  successively, 
and  leveled  in  each  position,  any  correction  being  made  in 
the  adjustments  that  may  appear  necessary. 

Care  should  be  taken  to  bring  the  wires  precisely  in 
focus,  and  the  object  distinctly  in  view,  so  that  all  errors  of 
parallax  may  be  avoided. 

This  error  is  seen  when  the  eye  of  an  observer  is  moved 
to  either  side  of  the  centre  of  the  eye-piece  of  a telescope, 
in  which  the  foci  of  the  object  and  eye-glasses  are  not 
brought  precisely  upon  the  cross-wires  and  object ; in  such 
a case  the  wires  will  appear  to  move  over  the  surface,  and 
the  observation  will  be  liable  to  inaccuracy. 

In  all  instances  the  wires  and  object  should  be  brought 
into  view  so  perfectly,  that  the  cross- wires  will  appear  to 
be  fastened  to  the  surface,  and  will  remain  in  that  position 
however  the  eye  is  moved. 

In  running  levels  it  is  best  wherever  possible,  that  equal 
fore  and  back  sights  should  be  taken,  so  as  to  avoid  any 
error  arising  from  the  curvature  of  the  earth. 

If  the  socket  of  the  instrument  becomes  so  firmly  set  m 


176 


LEVELING  INSTRUMENTS. 


the  tripod-head  as  to  be  difficult  of  removal  in  the  ordinary 
way,  the  engineer  should  place  the  palm  of  his  hand  under 
the  wye-nuts  at  each  end  of  the  bar,  and  give  a sudden 
upward  shock  to  the  bar,  taking  care  also  to  hold  his  hands 
so  as  to  grasp  it  the  moment  it  is  free. 


Fig.  44. 

Price  as  shown,  with  tripod,  $90.00. 


Our  fifteen-inch  Level  is  shown  in  Fig.  44;  it  has  the 
same  arrangement  of  sockets,  tripod,  &c.,  as  the  larger 
instruments,  but  no  pinion  movement  to  the  eye-piece.  The 
leveling-head  remains  attached  to  the  spindle,  and  is  packed 
with  it  in  the  box  ; it  is  also  somewhat  smaller  and  lighter 
than  those  of  the  other  sizes. 


Weight  of  Levelvig  Instruments . 

The  average  weights  of  the  different  sizes  of  this  instru- 
ment, exclusive  of  the  tripod-legs,  are  as  follows : 

15-inch  telescope,  with  leveling  head Hi1  uS* 

18-inch  u “ u 

20-inch  “ “ rp  44 

32-inch  “ “ 14 


LEVELING  INSTRUMENTS. 


177 


THE  ARCHITECTS’  LEVEL. 


Fig.  45. 


Price  as  shown,  with  tripod,  $45.00. 

The  figure  represents  the  level  introduced  by  us  nine  years 
ago,  and  which  has  since  been  very  largely  used  by  architects, 
builders,  and  millwrights  in  all  sections  of  the  country. 

It  has  a telescope  of  11  inches,  mounted  in  wyes  as  usual; 
furnished  with  the  accessories  of  the  larger  instruments, 
and  adjusted  in  the  same  manner. 

The  leveling-head  has  the  ordinary  screws  and  a clamp  to 
the  spindle,  but  no  tangent  movement;  it  has  also  a horizontal 
circle  of  3 inches  diameter,  fitted  to  the  upper  end  of  the 
socket  and  turning  readily  upon  it;  the  circle  is  graduated 
to  degrees,  figured  from  0 to  90  each  way,  and  is  read  to  five 
minutes  by  a vernier  which  is  fixed  to  the  spindle. 

* The  telescope  is  directed  to  any  object  by  hand,  the  spindle 
turning  readily  in  its  socket,  but  can  be  clamped  in  any 
position  by  the  clamp-screw  shown  under  the  circle. 


178  LEVELING  INSTRUMENT-. 

The  instrument  is  placed  either  upon  a light  tripod  as  in 
the  figure,  or  a small  triangular  plate  termed  a “ trivet/’ 
having  three  sharp  iron  points  by  which  it  is  firmly  set 
upon  any  surface  of  wood  or  stone ; both  tripod  and  trivet 
are  furnished  with  the  level. 

A short  piece  of  tube  called  a shade  is  also  supplied,  to 
be  put  on  over  the  object-glass  to  protect  it  from  the  glare 
of  the  sun  when  the  telescope  is  directed  towards  it. 

The  Adjustments  of  this  little  instrument  are  made 
precisely  as  described  in  our  account  of  the  larger  instru- 
ments— they  are  not  liable  to  derangement,  and  will  require 
ordinarily  but  little  attention. 

To  Use  the  Architects’  Level . 

The  instrument  should  be  set  up  firmly  upon  the  tripod 
or  trivet,  and  in  a position  as  nearly  level  as  practicable, 
the  telescope  placed  over  either  pair  of  leveling-screws,  and 
the  bubble  brought  into  the  centre  by  turning  the  opposite 
screws  with  the  thumb  and  forefinger  of  each  hand,  the 
thumbs  being  both  turned  in  or  out  as  may  be  needed,  and 
both  screws  brought  to  a bearing  in  the  little  cups  under- 
neath. Having  brought  the  bubble  into  the  centre  of  the 
vial,  turn  the  telescope  over  the  other  pair  of  screws,  and 
repeat  the  same  operation. 

If  the  bubble  runs  to  either  end,  bring  it  half-way  back 
by  the  capstan-head  screws  at  the  ends,  and  go  over  the 
adjustment  until  the  bubble  will  stand  in  the  centre  in 
every  position,  when  the  instrument  will  be  ready  for  use. 

Now,  bring  the  object  and  eye-glasses  into  focus  upon 
the  object  as  before  described,  and  the  horizontal  cross-wire 
will  give  any  number  of  points  required,  which  will  all  be 
in  the  same  level  line. 

A long  strip  of  board,  held  erect,  will  answrer  as  a rod, 
and  a line  in  pencil  drawn  across  it  at  the  part  cut  by  the 


LEVELING  INSTRUMENTS. 


179 


horizontal  wire  will  give  the  height  of  the  starting-point ; 
and  any  different  points  on  the  rod,  either  above  or  below 
indicated  by  the  cross-wire,  will  show  the  difference  in 
height  of  the  various  points  assumed,  as  compared  with  the 
starting-point. 

In  laying  off  angles  with  the  Level,  the  bubble  should 
first  be  brought  into  the  centre  as  before  described,  and  tfie 
vertical  cross-wire  made  to  cut  the  object  or  line  from 
which  the  angle  is  to  be  taken.  Then  the  spindle  being 
clamped  by  the  little  milled-head  screw  under  the  circle, 
the  circle  is  turned  around  by  hand,  until  the  zero  or  centre- 
points  of  both  the  circle  and  vernier  are  made  to  coincide — 
then  loosen  the  clamp-screw,  turn  the  telescope  to  the  point 
desired,  and  the  angle  between  the  two  points  will  be  read 
off  on  the  circle. 

The  point  underneath  the  Level  is  easily  indicated  by 
the  point  of  the  plummet  suspended  from  the  tripod. 

Of  course  it  will  be  understood  that,  by  the  use  of  the 
vernier,  angles  can  be  read  on  the  circle  to  five  minutes  of 
a degree,  but  ordinarily  only  even  angles  will  be  taken,  and 
the  centre-line  of  the  vernier  will  alone  be  used. 

In  many  situations,  after  the  walls  of  a building  have 
been  carried  up  to  any  required  height,  it  becomes  difficult 
to  set  up  the  tripod,  and -in  this  case  the  Level  is  screwed 
upon  the  little  trivet,  which  can  be  set  upon  the  wall,  or  a 
piece  of  board  tacked  to  the  building,  or  indeed  upon  any 
surface  nearly  level  and  not  less  than  six  inches  square. 

To  illustrate  the  value  of  this  instrument  in  laying  out 
the  sites  of  buildings,  let  it  be  supposed  that  it  is  desired  to 
erect  a building  0 D,  Fig.  46,  at  right  angles  to  a building 
A B,  and  at  a given  distance  from  its  front. 

First — Set  up  the  level  at  E,  and  carefully  centre  the  bub- 
ble, the  point  of  the  plummet  below  indicating  the  required 
distance  of  the  side  of  the  new  building  from  the  front  A B. 


180 


LEVELING  INSTRUMENTS. 


A E Next,  measure  off  the  same 

distance  at  the  other  corner  of 
j A B,  and  having  erected  the 

| rod,  sight  upon  it  with  the  tele- 

B F scope,  and  clamp  to  spindle. 

Now,  carry  the  rod  the  re- 
quired distance  from  B,  andj 
move  it  from  side  to  side,  until 
c p it  is  again  in  line  with  the  tele- 

| scope,  as  at  C. 

j . Remove  the  instrument,  and 
| having  carefully  set  it  over 

^ ® the  point  C by  the  plummet, 

FlG‘  and  brought  the  bubble  into 

the  centre  as  before,  set  the  telescope  again  upon  the  rod 
placed  at  E or  F,  clamp  to  spindle,  bring  the  circle  to  0 
with  the  zero  of  the  vernier — unclamp  and  turn  the  vernier 
to  90  degrees— it  will  give  a point  D at  any  required  dis- 
tance from  C,  and  C D will  be  the  side  of  the  proposed 
building.  The  side  C G is  determined  by  turning  the  tele- 
scope around  until  the  vernier  is  in  line  with  the  other  0 of 
the  circle,  and  thus  the  corner  C,  and  the  two  sides  C D 
and  C Gr,  are  at  once  set  off,  and  the  remaining  corner  H 
easily  ascertained  by  making  D H and  Gr  H equal  to  C Gr 
and  C D respectively. 

Other  applications  of  the  Level — as  the  setting  of  floor 
timbers,  of  window  and  door  sills,  the  leveling  of  floors,  etc., 
will  readily  occur  to  one  who  has  been  engaged  in  building, 
where  it  can  be  made  of  very  great  and  increasing  advan- 
tage, as  he  becomes  familiar  with  its  use. 

To  the  millwright,  such  a level  is  almost  indispensable  in 
the  lining  and  leveling  of  shafting,  the  ascertaining  of  the 
fall  of  water  obtainable,  and  the  overflow  of  land  by  a mill- 
pond, which  may  be  determined  upon. 


LEVELING  INSTRUMENTS. 


181 


The  extensive  farmer  will  find  it  of  great  value  in  laying 
out  drains,  determining  their  location,  the  heights  of 
springs,  etc. 

Indeed,  we  believe  that  as  this  little  Level  shall  become 
more  widely  known,  its  extreme  cheapness,  simplicity,  and 
excellence  will  create  for  it,  among  all  intelligent  and  enter- 
prising Architects,  Builders,  Millwrights,  and  Farmers,  a de- 
mand which  will  constantly  increase  in  all  parts  of  the  country. 


THE  DRAINAGE  LEVEL. 


Fig.  47. 

PRICES. 


Farmers1  or  Drainage  Level,  with  jacob-staff  mountings  — $15  00 

do  do  with  plain  tripod 20  00 

do  do  with  tripod  and  leveling  screws  25  00 

The  figure  represents  a level  just  devised  by  us  combining 
the  extremes  of  simplicity  and  compactness  with  real  effi- 
ciency, and  all  at  a very  moderate  cost.  The  level  and 
telescope  with  cross-wires  are  both  inclosed  and  secured  in 
a strong  outside  case  of  brass  from  8 to  9 inches  long, 
2 inches  wide,  and  inches  high,  oval  in  form. 

The  ends  of  the  case  are  thickened,  so  as  to  be  faced  off, 


182 


LEVELING  INSTRUMENTS. 


and  thus  made  parallel,  each  to  each,  on  the  two  opposite 
sides. 

A small  socket  screws  into  the  under-side  of  the  case, 
and  is  fitted  to  a ball-spindle,  by  which  it  is  made  approx- 
imately level,  and  then  precisely  so,  by  the  small  leveling- 
screws  as  shown.  When  desired  the  leveling-head  can  be 
dispensed  with,  and  the  instrument  leveled  on  the  ball  alone. 

This  instrument  is  adjusted  nearly  as  simply  as  an  ordi- 
nary masons’  or  builders’  level ; the  spirit-level,  by  reversing 
from  end  to  end  on  the  lower  faces  of  the  case,  and  making 
the  corrections  by  the  two  screws  in  line  with  the  level 
tube  ; the  telescope,  by  applying  the  opposite  faces  to  the 
same  surface,  and  bringing  the  telescope  cross-wire  by  two 
screws,  one  on  each  face,  so  as  to  cut  the  same  point  in 
both  positions  of  the  case. 

When  the  socket  is  screwed  to  the  case,  and  the  instru- 
ment revolved  upon  its  spindle,  the  level  is  made  to  remain 
in  the  centre  in  all  positions  by  four  screws,  two  on  each 
side  of  the  flange  of  the  socket  underneath,  the  pair  on  one 
side  being  loosened,  and  that  on  the  opposite  tightened, 
until  the  correction  is  made. 

It  will  of  course  be  understood  that  these  adjustments  are 
always  made  by  the  maker,  and  are  not  liable  to  derange- 
ment in  the  ordinary  use  of  the  level. 

The  advantages  of  this  level  in  the  work  of  the  farmer, 
manufacturer,  and  builder  will  be  apparent  on  a simple  in- 
spection ; for  not  only  can  drains  be  located  and  leveled, 
the  height  of  springs  ascertained,  the  accurate  levels  of  lines 
of  shafting,  floor-timbers,  sills,  etc.,  be  determined,  but 
when  removed  from  its  socket  it  can  be  applied,  either  by 
itself  or  on  a straight-edge,  to  the  leveling  of  any  surfaces 
of  stone,  wood,  or  metal. 

The  simple  sliding  leveling  rod  (Fig.  53)  hereafter  de- 
scribed, is  intended  for  use  with  this  instrument,  if  desired. 


LEVELING  RODS. 


183 


•c 

PM 


.§ 


6 

£ 


LEVELING  RODS. 

The  various  leveling  rods  used  by  Amer- 
ican engineers  are  made  in  two  or  more 
parts,  which  slide  from  each  other  as  they 
are  extended  in  use. 

THE  PHILADELPHIA  ROD. 

This  rod  is  made  of  two  strips  of  cherry, 
each  about  three-fourths  of  an  inch  thick 
by  one  and  a half  inches  wide  and  seven 
feet  long,  connected  together  by  two  metal 
sleeves,  the  upper  one  of  which  has  a clamp- 
ing-screw for  fastening  the  two  parts  to- 
gether when  the  rod  is  raised  for  a higher 
reading  than  seven  feet. 

Both  sides  of  the  back  strip  and  one  side 
of  the  front  one  are  planed  out  one-sixteenth 
of  an  inch  below  the  edges;  these  depressed 
surfaces  are  painted  white,  divided  into  feet, 
tenths  and  hundredths  of  a foot,  and  the 
feet  and  tenths  figured. 

The  front  piece  reads  from  the  bottom 
upward  to  seven  feet,  the  foot  figures  being 
red  and  an  inch  long,  the  tenth  figures  black 
and  eight-tenths  of  an  inch  long.  When  the 
rod  is  extended  to  full  length  the  front  sur- 
face of  the  rear  half  reads  from  seven  to 
thirteen  feet,  and  the  whole  front  of  the  rod 
is  figured  continuously  and  becomes  a self- 
reading rod  thirteen  feet  long. 

The  back  surface  of  the  rear  half  is  figured 
from  seven  to  thirteen  feet,  reading  from 
the  top  down;  it  has  a scale  also  by  which 


184 

the  rod  ii 
extended. 


LEVELING  RODS. 

read  to  two  hundredths  of  a foot  as  it  is 
The  target  is  round  and  made  of  sheet-brass 
raised  on  the  perimeter  to  increase  its  strength, 
and  is  painted  in  white  and  red  quadrants ; 
it  has  also  a scale  on  its  chamfered  edge, 
reading  to  two  hundredths  of  a foot. 

When  a level  of  less  than  seven  feet  is 
desired  the  target  is  moved  up  or  down  the 
front  surface,  the  rod  being  closed  to- 
gether and  clamped ; but  when  a greater 
height  is  required  the  target  is  fixed  at  seven 
feet  and  the  rear  half  slid  out,  the  scale-  on 
the  back  giving  the  readings  like  those  of  the 
target  to  two  hundredths  of  a foot. 

THE  BOSTON  ROD 

Is  formed  of  two  pieces  of  light  mahogany 
or  baywood,  each  about  six  feet  long,  and 
sliding  easily  by  each  other  in  either  direc- 
tion. 

One  side  is  furnished  with  a clamping  piece 
and  screw,  and  a small  vernier  at  each  end, 
the  other  or  front  piece  carries  the  target  and 
has  on  each  side  a strip  of  satin  wood  inlaid 
upon  which  divisions  of  feet,  tenths  and  hun- 
dredths are  marked  and  figured. 

The  target  is  a rectangle  of  wood  fastened 
on  the  front  half,  is  painted  black  and  white 
and  has  its  middle  line  just  three-tenths  above 
the  end  of  the  rod. 

Each  tenth  of  the  rod  is  figured  decimally 
in  three  figures  or  to  hundredths  of  a foot, 
and  by  the  verniers  is  read  to  thousandths. 

The  target  being  fixed,  when  any  height 


LEVELING  RODS. 


185 


is  taken  above  six  feet,  the  rod  is  changed 
end  for  end,  and  the  divisions  read  by  the 
other  vernier  ; the  height  to  which  the 
rod  can  be  extended  being  a little  over 
eleven  feet. 

This  kind  of  rod  is  very  convenient 
from  its  great  lightness,  but  the  parts  are 
made  too  frail  to  endure  the  rough  usage 
of  this  country,  and  therefore  American 
engineers  have  generally  given  the  prefer- 
ence to  others,  made  heavier  and  more 
substantial. 

THE  NEW  YORK  ROD. 

This  rod,  which  is  shown  in  the  engrav- 
ing as  cut  in  two,  so  that  the  ends  may 
be  exhibited,  is  made  of  maple,  in  two 
pieces  like  the  former,  but  sliding  one 
from  the  other,  the  same  end  being  always 
held  on  the  ground,  and  the  graduations 
starting  from  that  point. 

The  graduations  are  made  to  tenths  and 
hundredths  of  a foot,  the  tenth  figures 
being  black,  and  the  feet  marked  with  a 
large  red  figure. 

The  front  surface,  on  which  the  target 
moves,  reads  to  about  six  and  a half  feet ; 
when  a greater  height  is  required,  the 
horizontal  line  of  the  target  is  fixed  at  the 
highest  graduation,  and  the  upper  half  of 
the  rod,  carrying  the  target,  is  moved  out 
of  the  lower,  the  reading  being  now  ob- 
tained by  a vernier  on  the  graduated  side, 
up  to  an  elevation  of  twelve  feet. 


186  LEVELING  HODS. 

The  mountings  of  this  rod  are  differently  made  by  dif- 
ferent manufacturers.  We  shall  give  those  which  we  have 
adopted. 

The  target  is  round,  made  of  thick  sheet  brass,  having, 
to  strengthen  it  still  more,  a raised  rim,  which  also  protects 
the  paint  from  being  defaced. 

The  target  moves  easily  on  the  rod,  being  kept  in  any 
position  by  the  friction  of  the  two  flat  plates  of  brass  which 
are  pressed  against  two  alternate  sides,  by  small  spiral 
springs,  working  in  little  thimbles  attached  to  the  band 
which  surrounds  the  rod. 

There  is  also  a clamp-screw  on  the  back,  by  which  it  may 
be  securely  fastened  to  any  part  of  the  rod. 

The  face  of  the  target  is  divided  into  quadrants,  by  hori- 
zontal and  vertical  diameters,  which  are  also  the  boundaries 
of  the  alternate  colors  with  which  it  is  painted. 

The  colors  usually  preferred  are  white  and  red;  some- 
times white  and  black. 

The  opening  in  the  face  of  the  target  is  a little  more  than 
a tenth  of  a foot  long,  so  that  in  any  position  a tenth,  or  a 
foot  figure,  can  be  seen  on  the  surface  of  the  rod. 

The  right  edge  of  the  opening  is  chamfered,  and  divided 
into  ten  equal  spaces,  corresponding  with  nine-hundredths 
on  the  rod  ; the  divisions  start  from  the  horizontal  line 
which  separates  the  colors  of  the  face. 

The  vernier,  like  that  on  the  other  side  of  the  rod,  reads 
to  thousandths  of  a foot. 

The  clamp,  which  is  screwed  fast  to  the  lower  end  of  the 
upper  sliding-piece,  has  a movable  part  which  can  be 
brought  by  the  clamp-screw  firmly  against  the  front  surface 
of  the  lower  half  of  the  rod,  and  thus  the  two  parts 
immovably  fastened  to  each  other  without  marring  the 
divided  face  of  the  rod. 


LEVELING  RODS. 


187 


and  six  feet 
instance,  and 
tained. 


Fig.  51  represents  another  form  of  the 
sliding  leveling  rod,  which  we  have  ventured 
to  name  the  Troy  Eod  ; this  is  a self  reading 
rod  up  to  six  feet,  or  can  be  read  by  a vernier 
on  the  rear  piece  to  thousandths  of  a foot  as 
usual. 

It  has  two  targets  as  shown  both  fastened 
to  the  front  half  of  the  rod,  the  lower  one 
having  its  centre  line  just  three-tenths  above 
the  end,  and  the  other  target  exactly  six  feet 
above  the  lower. 

There  is  a clamping  piece  with  screw  on 
the  back  of  the  rod  and  below  the  target,  by 
which  the  two  parts  are  clamped  together 
when  desired. 

The  face  of  the  front  piece  is  recessed  like 
that  of  the  Philadelphia  Rod,  painted  white, 
divided  to  feet  and  hundredths,  and  figured 
as  represented. 

The  side  of  the  front  half  is  divided  to 
feet  and  hundredths,  read  by  a vernier 
on  the  top  of  the  rear  half  to  thousandths, 
and  figured  from  the  top  downwards,  be- 
ginning with  three-tenths,  that  being  the 
height  of  the  centre  line  of  the  lower 
target. 

When  a level  of  less  than  six  feet  is  taken 
on  the  rod  the  observation  is  made  by  the 
lower  target,  and  the  reading  is  direct  as 
given  on  the  side ; but  when  a greater  height 
is  taken  the  upper  target  is  sighted  upon, 
added  to  the  reading  on  the  side  in  every 
thus  a reading  up  to  twelve  feet  readily  ob- 


Fig.  52. — New  York  Rod , in  3 parts.  Price,  $18.00. 


188  LEVELING  ROES. 

THE  NEW  YORK  ROD. 

( Patented  Oct . 23,  1883.) 

In  S or  Jf  Parts. 

We  have  just  introduced  a modification  of 
this  favorite  rod,  which  we  believe  will  be 
generally  approved. 

In  the  new  rod  as  shown  in  Fig.  52,  a 
third  or  fourth  piece  is  added  to  the  two  of 
the  old  rod,  giving  thus  a rod  of  greater 
length,  and  at  the  same  time  making  it  more 
compact  and  portable. 

The  divisions, verniers,  readings,  and  target 
are  the  same  as  those  of  the  old  rod. 

We  make  two  varieties  of  the  three-parted 
rod,  one  sliding  to  allow  a reading  of  thirteen 
feet  and  the  other  extending  to  fourteen  feet; 
the  first  when  closed  is  only  five  feet  long, 
the  last  but  a little  over  five  and  a half  feet. 

Our  four-parted  rod  is,  when  closed,  but 
five  feet  in  length,  but  can  be  extended  t6 
sixteen  feet.  Price,  $20.00. 


THE  ARCHITECTS’  ROD. 

This  is  a very  light  and  simple  sliding  rod, 
made  of  maple,  m two  equal  parts,  each  seven- 
eighths  of  an  inch  square,  and  when  closed 
about  five  feet  six  inches  long. 

As  shown  in  Fig.  53  the  front  half  is 
divided  on  two  sides  to  feet,  tenths,  and 
hundredths,  reading  by  verniers  on  the  target 
and  side  to  thousandths  of  a foot. 

The  target  is  smaller  than  those  of  the  rods 
already  described  but  of  sufficient  size,  and 


LEVELING  RODS. 


189 


moves  on  the  closed  rod  when  levels  of  less 
than  five  feet  and  four-tenths  are  to  be 
taken. 

When  a greater  height  is  needed  the  target 
is  fixed  at  the  highest  division,  the  front  half 
carried  above  the  rear  part,  and  clamped  at 
any  point  desired  by  the  clamp-screw,  as 
shown,  the  height  being  now  read  off  by 
the  vernier  on  the  lower  half  up  to  ten  feet. 

This  rod  is  adapted  for  use  with  any  level, 
and  is  so  light  and  efficient  that  we  believe 
it  will  come  into  general  use  ; when  it  is  to  be 
used  by  an  Architect,  the  divisions  are  made 
in  feet,  inches,  and  sixteenths,  and  no  verniers 
are  then  required. 

METRIC  RODS. 

Besides  the  usual  divisions  of  the  leveling 
rods  into  parts  of  a foot,  we  also  divide  both 
the  Philadelphia  and  New  York  Rods  into 
meters,  decimeters,  and  centimeters,  the 
scales  on  the  target  and  sides  of  the  rods 
reading  the  centimeters  to  millimeters. 


TELEMETER  RODS. 

We  also  make  what  is  termed  a Telemeter 
Rod,  formed  of  two  pieces  of  pine,  each  three 
and  a half  inches  in  width,  seven-eighths  of 
an  inch  thick,  and  six  feet  long. 

Both  sides  of  the  rods  are  painted  white, 
the  inner  surfaces  being  also  recessed  to  pro- 
tect the  divided  surface,  with  divisions  in 
black  of  feet,  tenths,  and  hundredths,  and  figured,  the  feet 
in  red,  the  tenths  in  black. 


190 


LEVELING  RODS. 


when  closed 
four  meters. 


The  two  pieces  are  connected  by  a strong 
iron  hinge,  and  folded  in  transportation  ; when 
in  use,  they  are  opened,  laid  flat,  and  joined 
firmly  in  line  by  a wooden  bar,  about  eighteen 
inches  long,  held  to  each  piece  by  two  strong 
brass  screws,  which  enter  into  metal  sockets 
secured  in  each  part  of  the  rod. 

This  is  a self-reading  rod,  and  is  often  used 
in  connection  with  the  micrometer  wires  to 
ascertain  distances  by  a simple  observation  in 
the  same  manner  as  the  Philadelphia  Rod 
already  described.  Price,  $12.00. 

ENGLISH  OR  TELESCOPIC  ROD. 

A rod  of  English  make  is  sometimes  used, 
in  which  the  two  smaller  upper  parts  slide  out 
of  a larger  and  lower  one  which  answers  as  a 
case;  when  closed  the  rod  is  five  feet  long,  and 
extends  to  fourteen  feet. 

It  is  divided  on  a recessed  face  to  feet,  tenths, 
and  hundredths,  the  divisions  being  painted 
and  figured  like  those  of  the  Philadelphia  and 
Telemeter  Rods. 

We  also  furnish  this  rod  with  divisions  in 
meters,  decimeters,  and  centimeters ; length 
one  and  a half  meters,  and  sliding  out  to 


PLA^E  TABLE. 


191 


THE  PLANE  TABLE. 

This  instrument,  which  has  been  so  largely  employed 
abroad  in  topography  and  map  drawing,  is  now  fast  coming 
into  use  in  our  own  country,  especially  in  colleges  and 
schools  where  the  study  of  surveying  is  pursued. 

To  further  popularize  the  Plane  Table  we  have  devised  a 
number  of  different  styles,  varying  mainly  in  the  Alidades 
furnished  with  each  and  supplying  in  all  the  grades  an 
excellent  instrument  at  a very  moderate  cost. 


Price  as  shown,  $130.00.  (See  No.  92  in  Price  List.) 

As  shown  in  Fig  54,  the  Plain  Table  consists  mainly  of 
a drawing-board  set  upon  a firm  tripod,  and  having  upon 


192 


PLANE  TABLE. 


its  upper  surface  a movable  straight  edge  or  Alidade 
arranged  either  with  sight-vanes  or  telescope,  by  which  it 
may  be  directed  to  any  given  point,  the  line  being  then 
drawn  on  the  paper  along  the  edge  of  the  Alidade. 

A rectangular  plate  of  brass  to  which  is  attached  a small 
compass,  and  two  spirit-levels  is  also  shown,  and  serves 
both  to  level  the  table  and  when  applied  by  the  edges 
parallel  to  the  zero  points  of  the  compass  circle,  to  deter- 
mine the  magnetic  bearing  of  the  lines  drawn  on  the  paper, 
or  the  direction  of  the  table  itself. 

The  table  is  made  of  wood  arranged  in  sections  so  as  to 
prevent  warping,  and  has  an  adjustable  wooden  roller  at 
each  end  by  which  the  paper  is  brought  down  snugly  to  the 
board,  or  upon  which  a long  sheet  can  be  rolled  and  un- 
rolled at  will. 

In  place  of  the  rollers,  sometimes,  and  often  in  combination 
with  them,  a number  of  brass  clamps  as  shown  are  used  in 
holding  the  paper  firmly. 

The  plumbing  arm  shown  in  the  figure  has  its  end 
brought  to  a point,  that  it  may  be  set  at  any  given  point 
on  the  paper,  the  plummet  hanging  from  the  under  arm 
determining  the  corresponding  point  on  the  ground;  the 
lower  arm  moves  upon  a hinge,  an  index  on  the  side  showing 
when  the  ends  of  the  two  arms  are  plumb  with  each  other 
as  applied  to  the  table. 

The  construction  of  the  socket  and  tripod-head  is  shown 
in  Fig.  55,  in  which  a represents  the  hemispherical  concave 
metal  cup  fastened  by  six  screws  to  the  wood  top  of  the 
tripod,  b the  upper  or  convex  part  fitting  nicely  into  the  cup 
and  clamped  to  it  at  will  by  the  clamping  piece  c and  nut 
d ; a strong  spiral-ring  in  the  hollow  cylinder  between  c 
and  d , serves  to  hold  the  two  spherical  surfaces  of  the  socket 
together,  and  allow  of  the  easy  movement  of  the  one  within 
the  other  in  the  leveling  of  the  table. 


PLAXE  TABLE. 


193 


The  flange  of  the  socket  l supports  the  table  and  is  con- 
nected with  its  under  surface  by  three  segments  of  brass, 
two  of  which  are  shown  at  e e ; these  are  brought  down 
firmly  upon  the  shoulder  of  the  flange  by  capstan-head 
screws  as  shown,  or  released  at  will,  thus  allowing  the  Plane 
Table  to  be  moved  horizontally  when  desired. 


Fig.  55. 


A set  of  three  leveling-screws  is  sometimes  added  for 
more  accurately  leveling  the  table,  but  ordinarily  the  pres- 
sure of  the  hand  upon  it  with  the  socket  alone  will  be  all 
that  is  required. 

When  desired  a tangent  movement  in  azimuth  may  also 
be  added. 


194 


PLAKE  TABLE. 


THE  ALIDADES. 

The  different  styles  of  our  Plane  Tables  vary  only  in  their 
Alidades,  of  which  we  make  four  kinds. 


Price  $15.00.  (See  No.  90  in  Price  List.) 

(1.)  The  first  or  most  simple  Alidade  is  shown  in  Pig.  56, 
and  consists  of  a brass  rule  or  straight  edge,  twenty  inches 
long  and  two  to  three  inches  wide,  at  the  ends  of  which  are 
screwed  sight- vanes,  like  those  of  the  ordinary  compass;  the 
edge  of  the  rule  being  chamfered  and  in  line  with  the  slots 
of  the  vanes. 


(2.)  Pig.  57  shows  the  simple  Alidade  (Pig.  56),  to  which 
is  fitted  the  telescopic  sight,  having  a level,  clamp  and 


PLANE  TABLE. 


195 


tangent,  and  vertical  circle  reading  to  five  minutes,  attached 
to  the  telescope,  which  is  also  supplied  with  micrometer 
wires. 

The  telescope  is  placed  in  line  with  the  straight  edge  as 
before. 

(3.)  The  third  style  of  Alidade  is  shown  in  the  cut  of  the 
Plane  Table  at  the  beginning  of  this  article,  the  brass  rule 
being  now  two  inches  wide,  except  where  it  is  expanded 
one-third  from  the  end  to  receive  the  base  of'the  column. 

The  column  supports  the  telescope  with  its  attachments, 
the  vertical  circle  now  being  divided  on  silver  and  reading 
to  single  minutes. 

The  telescope  is  nine  inches  long,  of  a power  of  20 
diameters,  provided  with  stadia,  and  adjusted  and  used  like 
that  of  the  Transit;  it  is  also  in  line  with  the  chamfered 
edge  of  the  rule. 


(4.)  In  the  Alidade  shown  in  Fig.  58,  the  telescope  is 
precisely  the  same  as  that  used  on  our  best  Transits,  being 
also  supplied  with  level,  clamp  and  tangent,  vertical  circle 
on  silver  reading  to  single  minutes,  and  micrometer  wires 
for  measuring  distances. 


196 


PLANE  TABLE, 


It  is  placed  on  the  brass  rule  precisely  like  that  of  the 
one  last  described,  and  is  adjusted  and  used  in  the  same 
manner. 

In  Using  the  Plane  Table  the  tripod  is  set  up 
firmly,  and  the  table  covered  with  paper,  placed  upon  the 
flange  of  the  socket,  and  secured  by  the  screws  e e,  Fig.  55  ; 
the  nut  d being  now  loosened  the  table  is  moved  by  the 
pressure  of  the  hand  on  different  parts  of  the  board,  until 
the  levels  on  the  plate  will  come  into  the  centre  on  any 
part  of  the  table.  The  nut  d is  then  screwed  up  and  the 
table  made  firm  ; any  place  on  the  paper  can  then  be 
assumed  as  the  starting-point,  its  position  over  a given  point 
on  the  ground  being  determined  by  the  plumbing-bar  and 
plummet.  From  the  given  point  on  the  paper,  sights  can 
then  be  taken  to  different  corners  of  the  field  and  lines 
drawn  on  the  paper  along  the  edge  of  the  Alidade,  and  thus 
a miniature  of  the  tract  be  traced  on  the  paper,  the  bearing 
of  any  line  being  ascertained  by  applying  the  side  of  the 
compass-plate  to  the  edge  of  the  Alidade  placed  on  that 
line. 

The  table  can  be  moved  horizontally  either  by  hand  on 
releasing  the  screws  e e , or  by  a tangent-screw  as  before 
described. 

The  measurement  of  distances  by  the  micrometer  wires 
of  the  telescope,  and  of  vertical  angles  by  the  circle  is 
effected  as  already  described  in  our  account  of  the  Transit. 


SMALLER  INSTRUMENTS  AND  APPLIANCES.  197 


SMALLER  INSTRUMENTS  AND  APPLIANCES. 

LOCKE’S  HAND  LEVEL 


Fig.  59.  Prices,  $9.00  and  $10.00. 


Consists  of  a brass  tube  about  six  inches  long,  having,  as 
shown  in  the  figure,  a small  level  on  top  and  near  the  object 
end,  there  being  also  an  opening  in  the  tube  beneath, 
through  which  the  bubble  can  be  seen,  as  reflected  by  a 
glass  prism,  immediately  under  the  level.  Both  ends  of  the 
tube  are  closed  by  plain  glass  settings  to  exclude  the  dust, 
and  there  is  at  the  inner  end  of  the  sliding  or  eye  tube  a 
semicircular  convex  lens,  which  serves  to  magnify  the  level 
bubble,  and  cross-wire  underneath,  while  it  allows  the 
object  to  be  clearly  seen  through  the  open  half  of  the 
tube. 

The  cross-wire  is  fastened  to  a little  frame  moving  under 
the  level  tube  and  adjusted  to  its  place  by  the  small  screw, 
shown  on  the  end  of  the  level  case.  The  level  of  any  object 
in  line  with  the  eye  of  the  observer  is  determined  by 
sighting  upon  it  through  the  tube  and  bringing  the  air- 
bubble  of  the  level  into  a position  where  it  is  bisected  by  the 
cross- wire. 

A short  telescope  is  sometimes  applied  in  place  of  the 
plain  glass  ends  and  enabling  levels  to  be  taken  at  greater 
distances  and  with  increased  accuracy. 


198 


SMALLER  INSTRUMENTS  AND  APPLIANCES. 


THE  ABNEY  LEVEL  AND  CLINOMETER. 


Fig.  60.  Price,  $15.00. 


The  Abney  Level,  Fig.  60,  is  an  English  modification  of 
that  shown  in  Fig.  59,  combining  with  it  an  excellent  clino- 
meter as  represented  in  the  cut. 

Here,  when  the  level  is  brought  to  the  centre  by  setting 
the  vernier  arm  to  zero,  on  the  divided  arc,  the  bubble  is 
seen  through  the  eye  end  and  the  level  ascertained  precisely 
as  with  the  Locke’s  Level.  And  the  main  tube  being  square 
it  can  be  applied  to  any  surface,  the  inclination  of  which 
may  be  ascertained  by  bringing  the  level  bubble  into  its 
centre,  and  reading  off  the  angle  to  five  minutes,  by  the 
vernier  and  arc. 

The  inner  and  shorter  arc  indicates  the  lines  of  different 
degrees  of  slope,  the  left-hand  edge  of  the  vernier  being 
applied  to  the  lines  and  the  bubble  brought  into  the  centre 
as  usual. 


SMALLER  INSTRUMENTS  AND  APPLIANCES. 


199 


THE  ODOMETER 

Is  an  instrument  designed  to  register  the  number  of  revolu- 
tions of  a wagon  wheel  of  a given  circumference,  and  thus 
indicate  distances  in  cases  where  extreme  accuracy  is  not 
required. 


Fig.  61.  Price,  $15.00. 


The  odometer  shown  in  Fig.  61,  on  the  left,  consists 
essentially  of  a square  brass  weight  or  pendulum,  hung 
within  a rectangular  frame  which  revolves  with  the  wheel, 
while  the  pendulum  remains  vertical.  Upon  the  front  face 
of  the  pendulum  are  two  brass  wheels  two  inches  in  dia- 
meter, the  inner  surfaces  of  which  are  in  contact,  the  edges 
of  both  uniting  to  make  a groove  corresponding  to  a worm 
cut  in  the  middle  of  a shaft  fastened  to  the  sides  of  the 
frame. 

The  front  wheel  has  one  hundred  teeth,  the  rear  one 
ninety-nine,  and  both  pitch  into  and  are  moved  by  the 
revolving  worm  of  the  frame. 

There  are  also  the  same  number  of  divisions  as  of  teeth 
on  each  wheel,  and  they  are  figured,  the  front  wheel  from 
0 to  100,  the  rear  one  from  0 to  9000.  The  front  wheel  has 
three  spokes,  an  index  being  also  cut  down  on  its  perimeter 
to  read  the  divisions  of  the  rear  wheel,  the  front  wheel  itself 


200  SMALLER  INSTRUMENTS  AND  APPLIANCES. 

being  read  by  a slender  steel  wire  fastened  to  the  brass 
weight  and  curving  over  the  worm,  so  as  to  be  immediately 
over  the  divisions  of  the  wheel.  Now  when  the  frame  is 
made  to  revolve  by  the  revolution  of  the  wagon  wheel,  the 
worm  will  turn  both  wheels,  and  each  will  be  moved  for- 
ward one  tooth  by  every  turn,  and  when  one  hundred  turns 
are  made,  the  front  wheel  will  have  moved  completely 
around,  and  the  index  of  its  zero  division  will  have  been 
carried  over  one  division  of  the  inner  wheel. 

And  thus  by  noting  the  positions  of  the  indices  of  both 
wheels  the  number  of  revolutions  of  the  wagon  wheel  can 
be  easily  obtained  up  to  9900,  when  both  wheels  will  be  at 
zero  again.  The  wagon  wheel  being  of  a given  size,  the 
number  of  feet  traveled  can  be  at  once  ascertained  by 
noting  the  readings  of  the  wheels,  at  the  beginning  and  end 
of  the  journey,  subtracting  one  from  the  other  and  multiply- 
ing the  perimeter  of  the  wagon  wheel  by  the  number  of 
turns  made. 

The  metal  case  of  this  odometer  is  inclosed  within 

a stout  leather  box  as 
shown  at  the  right  of 
Fig.  61.  The  opening 
through  which  the  rect- 
angular frame  is  inserted 
or  removed  when  the 
reading  of  the  register  is 
desired  is  covered  with  a 
leather  flap  secured  by  a 
strap  and  buckle  as  shown 
in  the  cut.  The  manner 
in  which  the  odometer 
case  is  attached  to  the 
wheel  is  shown  in  Fig.  62. 
The  Odometer  in  use 


SMALLER  INSTRUMENTS  AND  APPLIANCES. 


201 


is  set  into  a metal  case,  which  is  itself  inclosed  in  a leather 
cover,  to  which  are  attached  strong  straps  for  fastening  the 
instrument  firmly  to  the  spokes  of  the  wagon  wheel. 

A form  of  the  Odometer  devised  by  us  is  represented  n 
Fig.  03,  the  pendulum  of  which  is  fastened  to  a shaft  turn- 
ing in  the  centre  of  a strong  circular  metal  box.  On  this 
shaft  and  turning  with  it  is  a pinion  giving  motion  to  a train 
of  wheels,  each  of  which  has  also  a shaft  to  the  end  of  which 
an  index  is  fastened.  There  are  dials  for  each  index  as  shown, 
and  the  number  of  turns  of  the  wagon  wheel  can  thus  be 
counted  np  to  100,000.  A strong  bezel  ring  with  thick  glass 
covers  the  dials  and  allows  them  to  be  easily  read. 


The  Odometer  is  securely  fastened  to  the  spokes  of  the 
wheel  by  three  carriage-bolts  as  shown,  there  being  also  a 


202 


SMALLER  INTSRUMENTS  AMD  APPLIANCES. 


thick  leather  washer  on  each  side  confined  between  the 
bottom  of  the  projecting  arms,  and  a metal  washer  of  same 
shape  on  the  other  side  of  the  spokes. 

In  using  this  Odometer  the  reading  of  the  dials  must  be 
taken  at  both  ends  of  the  journey,  the  one  subtracted  from 
the  other,  and  the  remainder  showing  the  number  of  turns 
of  the  wagon  wheel,  multiplied  into  its  perimeter  as  before 
described. 

Leveling  Adopter . — We 
have  just  introduced  the  appli- 
ance shown  in  Fig.64,  at  a , for  use 
with  the  Pocket  Compasses,  &c., 
giving  in  connection  with  the 
ball,  a rapid  and  accurate  means 
of  leveling  any  of  the  smaller 
instruments. 

Its  weight  is  less  than  one 
pound;  it  can  be  attached  to 
the  lighter  tripods  by  merely 
removing  the  brass  cap,  and  its  value  and  use  are  apparent 
on  inspection.  Price,  $5.00.  (See  Price  List  No.  173.) 

We  also  make  a larger  size  of  the  adopter  for  use  with  our 
larger  compasses.  Price,  $7.00.  (See  Price  List  No.  126.) 


GENERAL  MATTERS. 


TRIPODS. 

In  the  tripods  of  all  our  instruments  the  upper  part  of 
the  leg  is  flattened,  and  slotted  to  fit  closely  on  each  side  of 
a strong  tenon,  projecting  from  the  under  side  of  the 
tripod-head,  there  being  also  a strong  brass  bolt  with  large 
head  and  nut  on  opposite  sides  of  the  leg,  by  which  it  is 
held  firmly  in  place. 

The  tripod-head  is  made  of  the  best  bell-metal,  the 
tenons  and  upper  part  being  cast  in  one  piece  and  firmly 
braced  together. 

The  legs  are  round,  and  taper  in  each  direction  from  a 
swell,  turned  about  one-third  the  way  down,  from  the  head 
to  the  point. 

The  point,  or  shoe,  is  a tapering  brass  ferule,  having  an 
iron  end  ; it  is  cemented,  and  riveted  firmly  to  the  wood. 

The  legs  of  all  our  tripods  are  about  four  feet  eight  inches 
long,  from  head  to  point.  We  make  four  sizes  of  tripods 
with  solid  legs,  which  we  will  now  separately  describe. 

1.  The  Heavy  Tripod 9 shown  with  the  Engineers’ 
Transit,  having  a brass  plate  of  four  and  one-fourth  inches 
diameter,  with  mahogany  legs  one  and  three-eighths  of  an 
inch  at  the  top,  one  and  three-fourths  at  the  swell,  and 


204 


GENERAL  MATTERS. 


one  and  an  eighth  at  the  point,  is  used  with  the  engineers’ 
transit,  and  larger  leveling  instruments. 

2.  The  Medium  Sized  Tripod,  shown  with  the 
Surveyors’  Transit,  has  a plate  of  same  diameter  as  above, 
and  mahogany  legs  which  are  one  and  one-eighth  of  an 
inch  at  the  top,  one  and  five-eighths  at  the  swell,  and  one 
and  one-sixteenth  at  the  point,  and  is  used  with  the 
surveyors’  transit,  the  light  engineers’  transit,  and  the 
fifteen-inch  level. 

3.  The  Compass  Tripod 9 seen  in  part  in  the  cut  of 
the  Vernier  Transit  Compass,  has  a brass  head  about 
three  inches  in  diameter,  and  legs  which  are  about  one  inch 
at  the  top,  one  and  three-eighths  at  the  swell,  and  seven- 
eighths  at  the  bottom. 

The  legs  are  usually  made  of  cherry,  sometimes  of  maho- 
gany, and  the  tripod  is  used  with  the  various  kinds  of  com- 
passes, and  with  the  vernier  transit  compass. 

4.  The  Voeket  Compass  Tripod  shown  with  the 
various  smaller  instruments,  has  a strong  bronze  head  and 
legs  which  are  nearly  three-fourths  of  an  inch  at  top  and 
bottom,  and  one  and  one-eighth  of  an  inch  in  the  swell. 

EXTENSION  TRIPODS. 

We  also  make  three  sizes  of  extension  tripods  of  which 
the  medium  size  is  shown  in  Fig.  17,  in  our  account  of 
the  Mountain  Transit,  and  is  used  with  the  lighter  instru- 
ments. 

. A larger  size  with  bronze  head  and  heavier  legs  is  used 
with  the  larger  transits  and  leveling  instruments;  and  a 
smaller  and  lighter  one  with  the  various  pocket  compasses. 


TRIPODS. 


205 


QUICK  LEVELING  TRIPOD. 

We  have  for  several  years  past  made  a quick  leveling 
arrangement,  which  was  patented  by  us  in  November  1878, 
and  has  given  general  satisfaction  ; it  is  specially  adapted  to 
tripod-heads  of  our  own  make,  but  can  also  be  applied  to 
those  of  other  makers,  as  shown  hereafter. 

The  arrangement  of  this  attachment  will  be  readily 
understood  by  inspection  of  the  following  cuts : 


To  use  the  quick  leveling  attachment,  screw  the  instru- 
ment on  the  tripod  as  usual ; if  not  nearly  level,  unscrew 
the  leveling-head  a very  little,  a bare  loosening  of  the  screw 
9 


206 


GENERAL  MATTERS. 


is  sufficient.  The  instrument  will  then  he  free  to  more 
upon  the  spherical  surfaces,  A B 0,  in  any  direction  required 
to  bring  the  plates  approximately  level,  and  will  be  held  in 
this  position  by  the  friction  of  the  same  surfaces. 

Now  screw  the  head  fast  again,  firmly  clamping  the  whole 
instrument  to  the  tripod.  The  final  adjustment  of  the  levels 
is  then  completed  by  the  use  of  the  leveling  screws. 

The  friction  of  the  spherical  surfaces  may  be  increased  or 
diminished  at  will,  by  turning  the  screws  (D)  which  com- 
press the  spiral-springs. 

Fig.  65  shows  the  Quick  Leveling  Tripod  with  shifting 
plate  for  use  with  transit. 


QUICK  LEVELING  ATTACHMENT. 


Fig.  66. 


TRIPODS. 


207 


Fig.  66  shows  the  Quick  Leveling  Tripod-head  designed 
for  level  or  transit,  and  without  shifting  plate. 


Fig.  67. 


Fig.  67  shows  the  Quick  Leveling  Attachment  as  screwed 
fast  to  a tripod  of  any  pattern  now  in  use. 

Pi  • ices . — As  shown  in  Figs.  65  and  66,  when  furnished 
with  a new  instrument,  $5.00.  For  same,  adapted  to  any 
instrument  already  in  use,  as  in  Fig.  67,  $6.00. 

JV.  H. — When  Fig.  67  is  ordered  for  any  instrument,  the 
lower  plate  of  the  leveling-head,  as  shown  in  outline  of  same 
figure,  or  the  brass  head  of  the  tripod,  the  legs  being 
removed,  may  be  sent  to  us  bv  mail  or  express,  prepaid, 
with  the  remittance  of — say  $7.00 — to  pay  for  attachment 
and  return  charges. 

Lacquering . 

All  instruments  are  covered  with  a thin  varnish,  made  by 
dissolving  gum  shellac  in  alcohol,  and  applied  when  the 
work  is  heated. 

As  long  as  this  varnish  remains,  the  brass  surface  will  be 
kept  from  tarnishing,  and  the  engineer,  by  taking  care  not 
to  rub  his  instrument  with  a dusty  cloth,  or  to  expose  it  to 


208 


GENERAL  MATTERS. 


the  friction  of  his  clothes,  can  preserve  its  original  freshness 
for  a long  time. 

Bronze  Finish . 

Instead  of  the  ordinary  brass  finish,  most  engineers  prefer 
instruments  blackened  or  bronzed.  This  is  done  with  an 
acid  preparation,  after  the  work  has  been  polished,  and 
gives  the  instrument  a very  showy  appearance,  besides  being 
thought  advantageous  on  account  of  not  reflecting  the  rays 
of  the  sun  as  much  as  the  ordinary  finish. 

We  finish  our  instruments  either  bright  or  bronze,  as 
may  be  preferred. 

If  no  direction  is  given,  we  usually  send  Transit  and 
Leveling  instruments  of  bronze  finish,  and  Compasses  of 
bright  finish. 


GENERAL  MATTERS. 


209 


CHAINS. 

Surveyors’  Chains . 

Four  Pole  Chains—  The  ordinary  surveyors’  chain 
is  sixty-six  feet,  or  four  poles  long,  composed  of  one  hun- 
dred links,  each  connected  to  the  other  by  two  rings,  and 
furnished  with  tally  marks  at  the  -end  of  every  ten  links. 

In  all  the  chains  we  manufacture,  the  rings  are  oval,  are 
sawed,  and  well  closed,  the  ends  of  the  wire  forming  the 
hook  being  also  filed  and  bent  close  to  the  link,  so  as  to  avoid 
the  danger  of  “kinking.” 

A link  in  measurement  includes  a ring  at  each  end. 

The  handles  are  of  brass,  and  each  forms  part  of  the  end 
links,  to  which  it  is  connected  by  a nut,  by  which  also  the 
length  of  the  chain  is  adjusted. 

The  tallies  are  also  of  brass,  and  have  one,  two,  three,  or 
four  notches,  as  they  are  ten,  twenty,  thirty,  or  forty  links, 
from  either  end ; the  fiftieth  link  is  rounded,  so  as  to  dis- 
tinguish it  from  the  others, 

Two  Pole  Chains . — In  place  of  the  four  pole  chain 
just  described,  many  surveyors  prefer  one  of  two  rods  or 
thirty-three  feet  long,  having  but  fifty  links,  and  counted 
by  its  tallies  from  one  end  in  a single  direction. 

Snap  for  Altering  Chains. — We  often  make  four 
pole  chains  so  arranged,  that  by  detaching  a steel  snap  in 
the  middle,  the  two  parts  can  be  separated,  and  then  one  of 
the  handles  being  removed  in  the  same  manner,  and  trans- 
ferred to  the  forty-ninth  link,  a two  pole  chain  is  readily 
obtained.  This  modification  is  made  whenever  desired,  and 
without  any  additional  charge. 

Sizes  of  Wire. — Our  surveyors’  chains  are  made  of  the 


210 


CHAINS. 


best  refined  iron  wire*  of  sizes  No.  8 or  10,  as  may  be  pre- 
ferred ; the  diameter  of  No.  10  wire  being  about  one-eighth 
of  an  inch,  and  that  of  No.  8 wire  nearly  a sixteenth  larger. 

Engineers’  Chains 

Differ  from  the  preceding,  in  that  the  links  are  each  12 
inches  long  ; the  wire,  also,  is  usually  much  stronger. 

They  are  either  fifty  or  one  hundred  feet  long,  and  are 
furnished  with  handles,  tallies,  &c.,  and  sometimes  with  a 
swivel  in  the  middle  to  avoid  being  twisted  in  use. 

In  place  of  the  round  rings  commonly  made,  we  have 
substituted  in  these,  and  our  other  chains,  rings  of  an  oval 
form,  and  find  them  almost  one-third  stronger,  though 
made  of  the  same  kind  of  wire. 

Sizes  of  Wire , &c . — The  wires  used  for  these  chains 
is  of  sizes  Nos.  8 and  10,  is  of  the  first  quality  and  the  whole 
chain  well  and  accurately  made. 

Steel  Chains . 

Chains  made  of  steel  wire,  though  more  costly  than  those 
which  we  have  just  described,  are  yet  often  preferred  on 
account  of  their  greater  lightness  and  strength. 

They  are  made  of  any  desired  size  or  length,  generally  of 
No.  10,  rarely  of  No.  8 wire,  and  are  very  stiff  and  strong. 

JB razed  Steel  Chains. — A very  portable  and  excellent 
measure  is  made,  by  a light  steel  chain,  each  link  and  ring 
of  which  is  securely  brazed,  after  being  united  together  and 
tested  ; the  wire  is  also  tempered. 

The  wire  generally  used  by  us  is  of  size  No.  12,  the  rings 
are  of  oval  form,  the  chain,  though  exceedingly  light,  is 
almost  incapable  of  being  either  broken  or  stretched. 

Our  steel  brazed  chains  have  been  found  exceedingly 
desirable  for  all  kinds  of  measurement,  and  for  the  use  of 


GENERAL  MATTERS. 


211 


engineers  upon  railroads  and  canals  have  almost  entirely 
superseded  the  heavier  chains. 

Grumman' & Patent  Chains . 

These  chains,  invented  and  patented  by  J.  M.  Grumman, 
of  Brooklyn,  N.  Y.,  are  made  of  very  light  steel  wire,  the 
links  being  finely  tempered,  and,  as  shown  in  the  illustration, 


Fig.  68. 


so  formed  at  the  ends  as  to  fold  together  readily,  and  thus 
dispense  with  the  use  of  rings. 

This  construction  gives  only  one-third  as  many  wearing 
points  as  the  ordinary  chain,  and  affords  the  utmost  facility 
for  repairs,  from  five  to  ten  extra  links  being  furnished  with 
each  chain,  which  have  only  to  be  sprung  into  place  to 
replace  such  as  may  have  been  broken  ; it  can  also  be  taken 
apart  at  any  link,  and,  by  having  a spring-catch  on  either 
handle,  be  made  of  any  length  desired.  These  chains  are 
made  of  three  different  sizes  of  wire — the  first  two,  termed 
drag-chains,  being  of  size  No.  12  and  15,  and  used  for 
measuring  on  the  surface,  like  the  ordinary  chain  ; and  the 
second,  called  the  “suspended-chain,”  for  very  accurate 
measurements,  made  of  No.  18  wire,  and  with  spring- 
balance,  thermometer  and  spirit-level  attachments,  to  be 
held  above  the  surface  when  in  use,  the  extremities  of  the 
chain  being  marked  upon  the  ground  by  the  points  of 
plummets  let  fall  from  the  ends  of  the  chain. 


212 


CHAIKS. 


The  drag-chains  are  all  that  are  needed  in  common  land 
surveys ; for  a mixed  practice  of  village  and  country  survey- 
ing, the  spring-balance  should  be  attached  to  the  drag- 
chains,  while  for  city  surveying  the  suspended  chain,  with 
all  its  attachments,  is  the  proper  instrument. 

We  have  purchased  the  patent  for  the  Grumman  chains, 
with  the  entire  right  to  make  and  sell  them,  and  shall  here- 
after be  able  to  furnish  them  promptly. 

Vara  Chains . 

The  Spanish  or  Mexican  Vara,  which  is  in  very  general 
use  in  Texas,  Mexico,  Cuba  and  South  America,  is  334 
inches  long.  The  chains  are  made  of  ten  or  twenty  varas, 
each  vara  being  usually  divided  into  five  links  ; a link,  in- 
cluding a ring  at  each  end,  is,  therefore,  6f  inches.  A chain 
of  ten  varas  has  fifty  links ; of  twenty  varas  one  hundred 
links.  Each  vara  is  marked  by  a round  brass  tally,  num- 
bered from  one  to  nine  in  the  ten-vara  chain,  and  from  one 
to  ten,  each  way,  in  the  twenty-vara  chain.  Sometimes, 
but  rarely,  the  vara  is  divided  into  four  links  ; a ten-vara 
chain  then  has  forty  links,  and  a twenty-vara,  eighty  links. 

Metre  Chains . 

The  French  Metre  is  very  generally  used  as  a standard  in 
South  America,  the  West  Indies,  &c.,  and  chains  of  ten  and 
twenty  metres  are  often  ordered ; they  are  made  either  of 
iron  or  steel  wire  as  desired,  the  number  of  links  to  a metre 
and  the  tallies  being  similar  to  those  of  the  Vara. 

Marking  Pins . 

In  chaining,  there  are  needed  ten  marking  pins,  or  chain 
stakes,  made  either  of  iron,  steel,  or  brass  wire,  as  may  be 


GENERAL  MATTERS. 


213 


preferred,  about  fourteen  inches  long,  pointed  at  one  end 
to  enter  the  ground,  and  formed  into  a ring  at  the  other, 
for  convenience  in  handling. 

They  are  sometimes  loaded  with  a little  mass  of  lead 
around  the  lower  end,  so  as  to  answer  as  a plumb  when 
dropped  to  the  ground,  from  the  suspended  end  of  the 
chain. 

To  Use  the  Chain . 

In  using  the  chain  its  length  must  be  taken  from  its 
extreme  ends,  and  the  pins  placed  on  the  outside  of  the 
handles ; it  must  be  drawn  straight  and  taut,  and  care- 
fully examined  to  detect  any  kinks  or  other  causes  of 
inaccuracy. 

Our  chains  are  all  carefully  tested  at  every  ten,  some- 
times at  every  link,  and  in  their  whole  length  by  the  U.  S. 
standard,  and  when  new  may  always  be  relied  upon  as 
correct. 

But  as  all  will  alter,  more  or  less,  after  long  use  in  the 
field,  it  will  be  best  for  the  surveyor  to  carefully  lay  down 
on  a level  surface  the  exact  length  of  the  chain  when  yet 
new,  marking  also  its  extreme  ends  by  monuments  which 
will  not  be  liable  to  disturbance. 

He  will  thus  have  a standard  measure  of  his  own  to 
which  the  chain  can  be  adjusted  from  time  to  time,  and 
again  be  used  with  perfect  confidence. 


214 


TAPE  MEASURES. 


TAPE  MEASURES. 

The  best  are  steel  tapes,  made  of  a thin  ribbon  of  steel. 
Chesterman’s  English  steel  tapes  are  jointed  at  intervals, 
and  wound  up  in  a leathern  case,  having  a folding  handle. 

Paine’s  American  steel  tapes  are  made  of  thin  steel  rib- 
bon, straight  spring  temper,  and  in  one  piece.  They  are  of 
narrower  and  heavier  ribbon  than  the  Chesterman,  and  can 
be  detached  from  the  case,  and  used  with  a pair  of  handles, 
with  compensation  scale  for  variations  of  temperature,  for 
chain  measurements.  These  tapes  are  wound  up  in  a leather 
or  japanned  case  as  may  be  desired,  having  a folding  handle. 
Paine’s  tapes  are  U.  S.  Standard  measure  at  62°  temperature, 
and  using  about  twelve  pounds  strain  with  a fifty-foot  tape, 
and  sixteen  pounds  strain  with  a hundred-foot  tape. 

These  tapes  are  of  all  lengths,  from  three  to  one  hundred 
feet,  divided  into  feet  and  inches,  and  links,  or,  more 
usually,  feet  and  tenths  of  a foot,  and  links,  the  figures 
and  graduations  being  raised  on  the  surface  of  the  steel. 

Note. — A 100  feet  tape  expands  for  each  10°  rise  in  temperature, 
one  inch  in  fourteen  hundred  feet. 

CHESTERMAN’S  METALLIC  TAPES. 

These  are  of  linen,  and  have  also  fine  brass  wires  inter- 
woven through  their  whole  length. 

They  are  thus  measurably  correct,  even  when  wet. 

They  are  mounted  like  the  steel  tapes,  of  like  lengths, 
and  similarly  graduated. 

STANDARD  STEEL  RIBBONS. 

These  are  made  of  a thin  ribbon  of  steel,  f to  \ inch  wide, 
33  feet  to  500  feet  in  length,  and  in  one  piece.  They  are 
coming  into  general  use  for  bridge  work,  also  for  testing 
chains  and  tapes.  They  are  graduated  and  mounted  as 
described  in  the  Price  List,  Nos.  345  to  348, 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


215 


TRAVERSE  TABLES. 


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6526 

30 

? 45 

0.9909 

0.1349 

1.9817 

0.2697 

2.9726 

0.4046 

3.9635 

0.5394 

4.9543 

0.6743 

15  S 

) 8 0 

9903 

1392 

9805 

2783 

9708 

4175 

9611 

5567 

9513 

6959 

82  0) 

) 15 

9897 

1435 

9793 

2870 

9690 

4305 

9586 

5740 

9483 

7175 

45' 

< 30 

9890 

1478 

9780 

2956 

9670 

4434 

9561 

5912 

9451 

7390 

30$ 

45 

9884 

1521 

9767 

3042 

9651 

4564 

9534 

6085 

9418 

7606 

15 

) 9 0 

9877 

1564 

9754 

3129 

9631 

4693 

9508 

6257 

9384 

7822 

81  0 

$ 15 

9870 

1607 

9740 

3215 

9610 

4822 

9480 

6430 

9350 

8037 

45 

30 

9863 

1650 

9726 

3301 

9589 

4951 

9451 

6602 

9314 

8252 

30 

; 45 

9856 

1693 

9711 

3387 

9567 

5080 

9422 

6774 

9278 

8467 

15 

$10  0 

9848 

1736 

9696 

3473 

9544 

5209 

9392 

6946 

9240 

8682 

o 

o 
c o 

) 15 

0.9840 

0.1779 

1.9681 

0.3559 

2.9521 

0.5338 

3.9362 

0.7118 

4.9202 

0.8897 

45  ) 

) 30 

9833 

1822 

9665 

3645 

9498 

54t>7 

9330 

7289 

9163 

9112 

30) 

) 45 

9825 

1865 

9649 

37301 

9474 

5596 

9298 

7461 

9123 

9326 

15) 

11  0 

9816 

1908 

9633 

3816 

9449 

5724 

9265 

7632 

9081 

9540 

79  0) 

; 15 

9808 

1951 

9616 

3902 

9424 

5853 

9231 

7804 

9039 

9755 

45/ 

< 30 

9799 

1994 

9598 

3987 

9398 

5981 

9197 

7975 

8996 

9968 

30) 

45 

9190 

2036 

9581 

4073 

9371 

6109 

9162 

8146 

8952 

1.0182 

15) 

; 12  0 

9781 

2079 

9563 

4158 

9344 

6237 

9126 

8316 

8907 

0396 

78  0) 

15 

9772 

2122 

9545 

4244 

9317 

6365 

9089 

8487 

8862 

0609 

45  C 

/ 30 

9763 

2164 

9526 

4329 

9289 

6493 

9052 

8658 

8815 

0822 

30) 

( 45 

0.9753 

0.2207 

1.9507 

0.4414 

2.9260 

0.6621 

3.9014 

0.8828 

4.8767 

1.1035 

15) 

) 13  0 

9744 

2250 

9487 

4499 

9231 

6749 

8975 

8998 

8719 

1248 

77  0) 

15 

9734 

2292 

9468 

4584 

9201 

6876 

8935 

9168 

8669 

1460 

45) 

30 

9724 

2334 

9447 

4669 

9171 

7003 

8895 

9338 

8618 

1672 

30) 

> 45 

9713 

2377 

9427 

4754 

9140 

7131 

8854 

9507 

8567 

1884 

15? 

) 14  0 

9703 

2419 

9406 

4838 

9109 

7258 

8812 

9677 

8515 

2096 

76  0) 

) 15 

9692 

2462 

9385 

4923 

9077 

7385 

8769 

9846 

8462 

2308 

45 ) 

) 30 

9681 

2504 

9363 

5008 

9044 

7511 

8726 

1 .0015 

8407 

2519 

30$ 

45 

9670 

2546 

9341 

5092 

9011 

7638 

8682 

0184 

8352 

2730 

15) 

< 15  0 

9659 

2588 

9319 

5176 

8978 

7765 

8637 

0353 

8296 

2941 

75  0) 

) 

Hep. 

| Lat. 

Dep. 

| Lat. 

l)ep.  | 

| Lat. 

jDep.J 

Lat. 

Dep.  | 

Lat. 

) 

Dist.  1.  ^ 

Dist2^ 

Dist.  3. 

Dist.  4. 

Dist 

TJT' 

j 

TRAVERSE  TABLE. 


217 


"^Dist?  7? 

^Dist?  8. 

Dist 

. 9.  " 

^DistTlO. 

Course 

Lat. 

Dep. 

Lat. 

Dep. 

Lat. 

Dep. 

Lat. 

Dep. 

Lat.  1 

Dep. 

0 15 

5.9999 

0.0262 

6.9999 

0.0305 

7.9999 

0.0349 

8.9999 

0.0393 

9.9999 

0.0436 

89  45  ' 

30 

9998 

0524 

9997 

0611 

9997 

0698 

9997 

0785 

9996 

0873 

30  { 

45 

9995 

0785 

9994 

0916 

9993 

1047' 

9992 

1178 

9991 

1309 

15  ) 

1 0 

9991 

1047 

9989 

1222 

9988 

1396 

9986 

1571 

9985 

1745 

89  0 ) 

15 

9986 

1309 

9983* 

1527 

9981 

1745 

9979 

1963 

9976 

2181 

45) 

30 

9979 

1571 

9976 

1832 

9973 

2094 

9969 

2356 

9966 

2618 

30) 

45 

9972 

1832 

9967 

2138 

9963 

2443 

9958 

2748 

9953 

3054 

15) 

2 0 

9963 

2094 

9957 

2443 

9951 

2792 

9945 

3141 

9939 

3490 

88  0) 

15 

9954 

2356 

9946 

2748 

9938 

3141 

9931 

3533 

9923 

3926 

45 

30 

9943 

2617 

9933 

3053 

9924 

3190 

9914 

3926 

9905 

4362 

30 

45 

5.9931 

0.2879 

6.9919 

0.3358 

7.9908 

0.3S38 

8.9896 

0.4318 

9.9885 

0.4798 

15 

3 0 

9918 

3140 

9904 

3664 

9890 

4187 

9877 

4710 

9863 

5234 

87  0) 

15 

9904 

3402 

9887 

3968 

9871 

4535 

9855 

5102 

9839 

5669 

45) 

30 

9888 

3663 

9869 

4273 

9851 

4884 

9832 

5494 

9813 

6105 

30 

45 

9872 

3924 

9850 

4578 

9829 

5232 

9807 

5886 

9786 

6540 

15? 

4 0 

9854 

4185 

9829 

48S3 

98  5 

5581 

9781 

6278 

9756 

6976 

86  0? 

15 

9S35 

4447 

9808 

5188 

9780 

5929 

9753 

6670 

9725 

7411 

45  ? 

30 

9815 

4708 

9784 

5492 

9753 

6277 

9723 

7061 

9692 

7846 

30? 

45 

9794 

4968 

9760 

5797 

9725 

6625 

9691 

7453 

9657 

8281 

15? 

5 0 

9772 

5229 

9734 

6101 

9696 

6972 

965S 

7844 

9619 

8716 

85  0) 

15 

5.9748 

0.5490 

6.9706 

0.6405 

7.9664 

0.7320 

8.9622 

0.8235 

9.9580 

0.9150 

45? 

30 

9724 

5751 

9678 

6709 

963 

7668 

9586 

8626 

9540 

9585 

30? 

45 

9698 

6911 

9618 

7013 

9597 

8015 

9547 

9017 

9497 

1.0019 

15? 

6 0 

9671 

6272 

9617 

7317 

9562 

8362 

9507 

9408 

9452 

0453 

84  0? 

15 

9643 

6532 

9584 

7621 

9525 

8709 

9465 

9798 

9406 

0887 

45  ? 

30 

96 14 

6792 

9550 

7924 

94S6 

9056 

9421 

1.0188 

9357 

1320 

30? 

45 

9584 

7052 

9515 

8228 

9445 

9403 

9376 

0578 

9307 

1754 

15) 

7 0 

9553 

7312 

9478 

8531 

9404 

9750 

9329 

0968 

9255 

2187 

83  0) 

15 

9520 

7572 

9440 

8834 

9360 

1.0096 

9280 

1358 

9200 

2620 

45) 

30 

9487 

7832 

9401 

9137 

9316 

0442 

9230 

1747 

9144 

3053 

30) 

45 

5.9452 

0.8091 

6.9361 

0.9440 

7.9269 

1.0788 

8.9178 

1.2137 

9.9087 

1.3485 

15? 

8 0 

9416 

8350 

9319 

9742 

9221 

1134 

9124 

2526 

9027 

3917 

82  0? 

^5 

9379 

8610 

9276 

1.0044 

9172 

1479 

9069 

2914 

8965 

4349 

45) 

30 

9311 

8869 

9231 

0347 

9121 

1825 

9011 

3303 

8902 

4781 

30) 

45 

9302 

9127 

9185 

0649 

9069 

2170 

8953 

3691 

8836 

5212 

15) 

9 0 

9261 

9386 

9138 

0950 

9015 

2515 

8892 

4079 

8769 

5643 

81  0) 

15 

9220 

9645 

9090 

1252 

8960 

2859 

8830 

4467 

8700 

6074 

45? 

30 

9177 

9903 

9040 

1553 

8903 

8204 

8766 

4854 

8629 

6505 

30? 

45 

9133 

1.0161 

89S9 

1854 

8844 

3548 

8700 

5241 

8556 

6935 

15? 

10  0 

9088 

0419 

8937 

2155 

8785 

3892 

8633 

5628 

, 8481 

7365 

80  0? 

15 

5.9042 

1.0677 

6.8883 

1.2456 

7.8723 

1.4235 

8.8564 

1.6015 

9.8404 

1.7794 

45  ? 

30 

8995 

(934 

8828 

2756 

8660 

4579 

8493 

6401 

8325 

8224 

30) 

45 

8947 

1191 

8772 

3057 

8596 

4922 

S421 

6787 

8245 

8652 

15? 

11  0 

8898 

1449 

8714 

3357 

8530 

5265 

8346 

7173 

8163 

9081 

79  0) 

15 

8847 

1705 

8655 

3656 

8463 

5607 

8271 

7558 

8079 

9509 

45? 

30 

8795 

1962 

8595 

3956 

8394 

5949 

8193 

7943 

7992 

9937 

30? 

45 

8743 

2219 

8533 

4255 

8324 

6291 

8114 

8328 

7905 

2.0364 

15? 

12  0 

8689 

2475 

8470 

4554 

8252 

6633 

8033 

8712 

7815 

0791 

7S  0? 

15 

8634 

2731 

8406 

4852 

8178 

6974 

7951 

9096 

7723 

1218 

45? 

30 

8578 

2986 

8341 

5151 

8104 

7315 

7867 

9480 

7630 

1644 

30? 

45 

5.8521 

1.3242 

6.8274 

1.5449 

7.8027 

1.7656 

8.7781 

1.9863 

9.7534 

2.2070 

15) 

13  0 

8462 

3497 

8206 

5747 

7950 

7996 

7693 

2 0246 

7437 

2495 

77  0) 

15 

8403 

3752 

8137 

6044 

7870 

8336 

7604 

0628 

7338 

2920 

45? 

30 

8342 

4007 

8066 

• 6341 

7790 

8676 

7513 

1010 

7237 

3345 

30? 

45 

8281 

4261 

7994 

6638 

7707 

9015 

7421 

1392 

7134 

3769 

15? 

14  0 

8218 

4515 

7921 

6935 

7624 

9354 

7327 

1773 

7030 

4192 

76  0 

15 

8154 

4769 

7846 

7231 

7538 

9692 

7231 

2154 

6923 

4615 

45? 

30 

8089 

5023 

7770 

7527 

7452 

2.0030 

7133 

2534 

6815 

5038 

30? 

45 

8623 

5276 

7693 

7822 

7364 

0368 

7034 

2914 

6705 

5460 

15 

15  0 

7956 

5529 

7615 

8117 

7274 

0706 

6933 

3294 

6593 

5882 

75  0) 

Dep. 

| Lat.  1 

Dep. 

| Lat. 

Dep.  , 

| Lat. 

Dep.  | 

Lat. 

J>ep-I 

Lat. 

( 

Dist.  6.  1 

Dist.  7. 

Dist.  8. 

Dist.  9.  I 

1 Dist 

7io~ 

Course  , 

218  TRAVERSE  TABLE. 


Course 

^DistTl^ 

^DisTIT^ 

Distnr^ 

Lit. 

Dep. 

Lat. 

Dep. 

Lat.. 

Dep. 

Lat. 

Dep. 

Lat.' 

Dep. 

15  15 

0.9648 

0.2630 

1.9296 

0.5261 

2.8944 

0.7891 

3.8591 

1.0521 

4.8239 

1.3152 

74  45 

30 

9636 

2672 

9273 

5345 

8909 

8017 

8545 

0690 

8182 

3362 

30  < 

45 

9625 

2714 

9249 

5429 

8874 

8143 

8498 

0858 

8123 

3572 

15  < 

16  0 

9613 

2756 

9225 

5513 

8838 

8269 

8450 

1025 

8063 

3782 

74  OS 

15 

9600 

2798 

9201 

5597 

8801 

8395 

8402 

1193 

8002 

3991 

45 ) 

30 

9588 

2840 

9176 

5680 

8765 

8520 

8353 

1361 

7941 

4201 

30) 

45 

9576 

2882 

9151 

5764 

8721 

8646 

8303 

1528 

7-879 

4410 

15/ 

17  0 

9563 

2924 

9126 

5847 

8689 

8771 

8252 

1695 

7815 

4619 

73  0? 

15 

9550 

2965 

9100 

5931 

8651 

8896 

8201 

1862 

7751 

4827 

45  ) 

30 

9537 

3007 

9074 

6014 

8612 

9021 

8149 

2028 

7686 

5035 

30? 

45 

0.9524 

0.3049 

1.9048 

0.6097 

2.8572 

0.9146 

3.8096 

1.2195 

4.7620 

1 5243 

15) 

18  0 

9511 

3090 

9021 

6180 

8532 

9271 

8042 

2361 

7553 

5451 

72  0) 

15 

9497 

3132 

8994 

6263 

8491 

9395 

7988 

2527 

7485 

5658 

45; 

30 

9183 

3173 

8966 

6346' 

8450 

9519 

7933 

2692 

7416 

5865 

30  ) 

45 

9469 

3214 

8939 

6429 

8408 

9643 

7877 

2858 

7347 

6072 

15  / 

19  0 

9455 

3256 

8910 

6511 

8366 

9767 

7821 

3023 

7276 

6278 

71  0? 

15 

9441 

3297 

8882 

6594 

8323 

9891 

7761 

3188 

7204 

6485 

45  ? 

30 

9426 

3338 

8853 

6676 

8279 

1.C014 

7706 

3352 

7132 

6690 

30? 

45 

9412 

3379 

8824 

6758 

8235 

0138 

7647 

3517 

7059 

6896 

15  s 

20  0 

9397 

3420 

8794 

6840 

8191 

0261 

7588 

3681 

6985 

7101 

o 

o 

15 

0.9382 

0.3461 

1.8764 

0.6922 

2.8146 

1.0384 

3.7528 

1.3845 

4.6910 

1.7306 

45 

30 

9367 

3502 

8733 

7004 

8100 

0506 

7467 

4008 

6834 

7510 

30 

45 

9351 

3543 

8703 

7086 

8054 

0629 

7405 

4172 

6757 

7715 

15 

21  0 

9336 

3584 

8672 

7167 

8007 

0751 

7343 

4335 

6079 

7918 

69  0? 

15 

9320 

3624 

8610 

7249 

7960 

0873 

7280 

4498 

6(00 

8122 

45 

30 

9304 

3665 

8608 

7330 

7913 

0995 

7217 

4600 

6521 

8325 

30 

45 

9288 

3706 

8576 

7411 

7864 

1117 

7152 

4822 

6440 

8528 

15 

22  0 

9272 

3746 

8544 

7492 

7816 

1238 

7087 

4984 

6359 

8730 

6S  0) 

15 

9255 

3786 

8511 

7573 

7766 

1359 

7022 

5146 

6277 

8932 

45) 

30 

9239 

3827 

8478 

7654 

7716 

1481 

6955 

5307 

6194 

9134 

30  l 

45 

0.9222 

0.3867 

1.8444 

0.7734 

2.7666 

1.1601 

3,6888 

1.5468 

4.6110 

1.9336 

15 

23  0 

9205 

3907 

8110 

7815 

7615 

1722 

6820 

5629 

6025 

9537 

67  0$ 

15 

9188 

3947 

8376 

7895 

7564 

1842 

6752 

5790 

5940 

9737 

95  ) 

30 

9171 

3987 

8341 

7975 

7512 

1962 

6682 

5950 

5853 

9937 

30 

45 

9153 

4027 

8306 

S055 

7459 

2082 

6612 

6110 

5766 

2.0137 

15 ) 

24  0 

9135 

4067 

8271 

8135 

7406 

2202 

6542 

6269 

5677 

0337 

66'  0) 

15 

9118 

4107 

8235 

8214 

7353 

2322 

6470 

6429 

5588 

0536 

45^ 

30 

9100 

4147 

8199 

8294 

7299 

2441 

6398 

6588 

5498 

0735 

30/ 

45 

9081 

4187 

8163 

8373 

7244 

2560 

6326 

6746 

5407 

0933 

15 

25  0 

9063 

4226 

8126 

8452 

7189 

2679 

6252 

6905 

5315 

1131 

65  0^ 

15 

0.9045 

0.4266 

1.8089 

0.8531 

2.7134 

1.2797 

3.617S 

1.7063 

4.5223 

2.1328 

45) 

30 

9026 

4305 

8052 

8610 

7078 

2915 

6103 

7220 

5129 

1526 

30) 

45 

9007 

4344 

8014 

8689 

7021 

3033 

6028 

7378 

5035 

1722 

15) 

26  0 

8988 

4384 

7976 

8767 

6964 

3151 

5952 

7535 

4940 

1919 

64  0> 

15 

8969 

4423 

7937 

8846 

6906 

3269 

5875 

7692 

4844 

2114 

45 ? 

30 

8949 

4462 

7899 

8924 

6848 

3386 

5791 

7848 

4747 

2310 

30? 

45 

8930 

4501 

7860 

9002 

6789 

3503 

5719 

8004 

4649 

2505 

15? 

27  0 

8910 

4540 

7820 

9080 

67C0 

3620 

5640 

8160 

4550 

2700 

63  0( 

15 

8890 

4579 

7780 

9157 

6671 

3736 

5561 

8315 

4451 

2894 

45  ( 

30 

8870 

4617 

7740 

9235 

6610 

3852 

5480 

8470 

4351 

3087 

30  < 

' 45 

0.8850 

0.4656 

1.7700 

0.9312 

2.6550 

1.3968 

3.5400 

'.8625 

4.4249 

2.3281 

15) 

28  0 

8829 

4695 

7659 

9389 

6488 

4084 

5318 

8779 

4147 

3474 

62  0) 

15 

8809 

4733 

7618 

9466 

6427 

4200 

5236 

8933 

4045 

3666 

45  ? 

30 

8788 

4772 

7576 

9543 

6365 

4315 

5153 

9086 

3941 

3858 

20? 

45 

8767 

4810 

7535 

9620 

6302 

4430 

5069 

9240 

3836 

4049 

15 

29  0 

8746 

4848 

7492 

9696 

6239 

4544 

4985 

9392 

3731 

4240 

61  0? 

1 15 

8725 

4886 

7150 

9772 

6175 

4659 

4900 

9515 

3625 

4431 

45  ( 

’ 30 

8704 

4924 

7407 

9848 

6111 

4773 

4814 

9697 

3518 

4621 

30 ) 

' 45 

8682 

4962 

7364 

9924 

6046 

4886 

4728 

9849 

3410 

4811 

15) 

\ 30  0 

8660 

5000 

7321 

1.0000 

5981 

1 5000 

4641 

2.0000 

3301 

5000 

60  0) 

Dep. 

| Lat. 

Dep. 

| Lat. 

Dep.  | 

| Lat. 

Dep 

| Lat. 

Dep.  | 

j Lat. 

Course  ) 

Dist.  1. 

Dist.  2. 

^DistJI^ 

Dist.  4. 

Dist.  5. 

TRAVERSE  TABLE. 


219 


Course 

Dist.  6. 

Dist.  7. 

Dist.  8. 

Dist.  9. 

Dist, 

. 10. 

( 

Lat. 

Dep. 

Lat. 

Dep. 

Lat. 

Dep. 

Lat. 

Dep. 

Lat. 

Dep. 

/ 

O ^ / 

15  15 

5.7887 

1 .5782 

6.7535 

1.8412 

7.7183 

2.1042 

8.6831 

2.3673 

9.6479 

2.6303 

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222 


W.  & L.  E.  GURLEY,  TftoY,  N.  Y. 


SUPPLEMENT 

TO 

TWENTY-FIFTH  EDITION  OF  MANUAL. 


J"  ^ 1ST  TX  .A.  DR,  1 B 8 4 . 


When  ordering  goods  always  state  what  edition  of  Manual,  and  number  in 
Catalogue. 

***  The  prices  in  this  Catalogue  may  vary  from  time  to  time,  on  account  of 
fluctuations  in  Market  Rates. 

This  Price  List  supersedes  all  previous  editions. 


DRAWING  INSTRUMENTS. 

To  guide  the  Surveyor  aud  Engineer  in  the  selection  of 
Drawing  Instruments,  we  here  add  a detailed  description, 
with  illustrations  and  prices  of  the  separate  pieces,  and 
cases  of  the  different  kinds  in  general  use. 

Those  we  shall  first  mention  are  of  Swiss  manufacture, 
and  are  of  the  finest  quality  and  finish. 

The  Brass  Instruments  are  used  in  Schools  and  elemen- 
tary practice. 

The  fine  German  Silver  Instruments  are  of  the  best 
German  make,  intended  for  Engineers,  Architects,  and 
Machinists. 


w.  & L.  E.  GURLEY,  TROY,  N.  Y.  223 

Parties  wanting  cases  made  up,  can  select  the  pieces,  and 
we  will  make  cases  to  suit,  at  an  additional  cost  of  from  $2 
to  815,  according  to  the  size  of  the  cases,  which  are  made 
of  morocco,  rosewood,  walnut,  or  mahogany. 

For  the  convenience  of  our  customers,  we  will  furnish 
any  articles  not  on  our  list,  but  described  in  the  catalogue 
of  any  American  manufacturer  or  dealer  in  mathematical 
intruments,  at  catalogue  prices. 


SPECIAL  NOTICE. 

Many  of  our  smaller  instruments,  such  as  drawing  instru- 
ments, pocket  compasses,  chains,  tapes,  small  packages  of 
paper  and  parts  of  large  instruments  can  be  sent  by  mail 
securely  packed,  and  at  much  lower  rates  than  are  charged 
by  express  companies.  Packages  not  exceeding  four  pounds 
in  weight  can  be  sent  in  this  way  within  the  United  States 
at  a cost  of  one  cent  per  ounce. 

In  all  cases  where  goods  are  to  he  sent  by 
mail,  the  cash  for  postage  as  well  as  for  the 
goods  must  accompany  the  order. 

All  articles  can  be  registered  at  an  extra  cost  of  ten  cents 
for  each  package  besides  regular  postage. 

We  are  not  responsible  for  goods  sent  by 
mail, 


224 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


SWISS  DRAWING  INSTRUMENTS. 


OF  GERMAN  SILVER,  EXTRA  FINE  FINISH. 


400.  401.  402. 


400.  401.  402. 

N°-  Price 

400. — Drawing  Compass,  joints  in  legs,  6J  inches  long,  with  pen,  pencil- 

holder,  needle  point,  lengthening  bar  and  dot.  pen $9  00 

401. —  Drawing  Compass,  6 inches  long,  with  pen,  pencil-holder,  lengthening 

bar  and  needle-point 6 50 

402.  — Drawing  Compass,  6|  inches  long,  with  fixed  Needle  Point  and  Loose 

Pen  and  Pencil  Points  and  Lengthening  Bar . .*. 6 00 

403.  — Hair  Spring  Dividers,  4£  inch 2 25 

404. —  “ “ 5^  inch 2 

405.  -Plain  Dividers,  4|  inch 1 

403.—  u 5 inch 1 

407. -  “ 6 inch 2 

408. — Drawing  Compass,  4 inch,  with  pen,  pencil-holder,  and  needle-point. . . 5 

409. — Drawing  Compass,  4 inch,  with  fixed  needle-point,  and  pen  and  pencil- 

point,  changeable 4 50 

410. — Proportional  Dividers,  inches  long,  finely  graduated  for  lines 8 00 

411. — Proportional  Dividers,  6.V  inches  long,  finely  graduated  for  lines  and 

polygons 8 75 

412.  — Proportional  Dividers,  9 inches  long,  finely  graduated  for  lines  and 

polygons 10  00 

413. — Proportional  Dividers,  9 inches  long,  with  micrometer  adjustment  (413), 

finely  graduated  for  lines  and  polygons 12  00 

414. — Proportional  Dividers,  8 inches  long,  with  rack  adjustment,  graduated 

for  lines 10  50 


£ 8 i?  8 8 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


225 


435. 


226 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


-Triangular  Compass $4X<25 

-Dotting  Pen,  with  one  wheel  2 qq 

-Dotting  Pen,  in  case,  best  article,  with  three  wheels 3 75 

-Road  or  Double  Drawing  Pen 3 75 

-Road  or  Double  Drawing  Pen,  Joint  on  each  side 3 00 

-Pocket  Dividers,  with  sheath 2 40 

-Bisecting  Dividers. 4 25 

-Universal  Compass,  with  points  to  shift 7 25 

“ turn 7 25 

“ “ “ change,  and  handles  to  bow  pen  and 

Pencil g 00 


429. 


430. 


431. 


433. 


434. 


435. 

-Dividers,  3£  inches  long,  with  two  fixed  Needle  Points $3  00 

Dividers,  3|  inches  long,  with  fixed  Needle  Point  ^md  Pen  Point 3 00 

Dividers,  3£  inches  long,  with  fixed  Needle  Point  and  Pencil  Point 3 00 

-Large  Steel  Spacing  Dividers,  5 inches 2 50 

Small  Steel  Spacing  Dividers,  3b  inches 1 50 

-Small  Steel  Spacing  Dividers,  3%  inches  long,  with  Needle  Points  2 40 

Small  Steel  Bow  Pen,  3£  inches 1 SO 

-Small  Steel  Bow  Pen,  with  Needle  Point 2 40 

Small  Steel  Bow  Pencil,  3^  inches 1 90 

-Small  Steel  Bow  Pencil,  with  Needle  Point 2 40 

-Bow  Pen,  German  Silver  “ 2 00 

Bow  Pen,  with  pencil-holder,  German  Silver,  with  Needle  Point 3 00 

Eccentric  Rule 2 00 

Drawing  Pen,  with  joint,  4£  inches  long 1 25 

“ “ 51  « 1 40 

“ 6 u 1 00 

Beam  Compass  furniture,  for  wood  beams.  $6  75  ; in  Morocco  box 7 00 

Horn  Curves,  A,  B,  C,  D,  E.  F.  each. . 65 

Drawing  Compass,  4 inches,  with  long  ivory  handle,  spring  and  micro- 
meter, with  two  pens,  pencil-holder  and  needle  point, 7 00 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


227 


a 


S 


442.  443.  444. 


228 


W.  & L.  E.  GURLEY,  TROY,  H.  Y. 


No.  Price 

450.— Polar  Planimeter,  with  printed  instructions $30  00 


By  means  of  Amsler’s  Polar  Planimeter  a person  entirely  ignorant  of 
Geometry  may  ascertain  the  area  of  any  planimetrical  figure,  no  mat- 
ter how  irregular  its  outlines  may  he,  more  correctly,  and  in  much 
shorter  time,  than  the  most  experienced  Mathematician  could  calcu- 
late it. 

The  management  of  the  instrument  can  be  easily  learned  in  half  an 
hour,  and  in  size  it  is  no  larger  than  a two-foot  folding  rule. 

The  Planimeter  indicates  square  feet  or  square  inches,  and  acres  for 
surveying. 

SETS  OF  EXTRA  FINE  SWISS  DRAWING 
INSTRUMENTS. 

The  following  sets  have  beautifully  finished  Mahogany  or  Walnut  Boxes, 

91  inches  long  by  6 inches  wide,  with  lock  and  key  and  tray. 

460. — Contains  pair  plain  Dividers,  No.  406. 

Set  of  Instruments,  No.  401. 

Steel  Spacing  Dividers,  No.  433. 

Steel  Bow  Pen,  3|  inches,  No.  435. 

Steel  Bow  Pencil,  3^  inches,  No.  437. 

Drawing  Pen,  No.  443. 

Triangular  Scale,  6 inch $21  00 

461. — Contains  pair  plain  Dividers,  No.  406. 

Set  of  Instruments,  No.  401. 

Do.  No.  408. 

Drawing  Pen,  No.  442. 

Do.  No.  444. 

Triangular  Scale,  6 inch 22  00 

462. — Contains  pair  plain  Dividers,  No.  406. 

Set  of  Instruments,  No.  401. 

Do.  No.  408. 

Bow  Pen,  German  Silver,  No.  439. 

Drawing  Pen,  No.  442. 

Do.  No.  444. 

Triangular  Scale,  6 inch, 


24  00 


w.  & L.  E.  GURLEY.  TROY,  N.  Y« 


229 


462. 

No. 

463. — Contains  pair  plain  Dividers,  No.  406 

Pair  Hair  Spring  Dividers,  No.  404 
Set  of  Instruments,  No.  401. 

Steel  Spacing  Dividers,  No.  433. 

Steel  Bow  Pen,  No.  435. 

Steel  Bow  Pencil,  No.  437. 

Drawing  Pen,  No.  442. 

Do.  No.  444. 

Triangular  Scale,  6 inch 

464. — Contains  pair  plain  Dividers,  No.  406. 

Pair  Hair  Spring  Dividers,  No.  404. 

Set  of  Instruments,  No.  401. 

Do.  No.  408. 

Bow  Pen,  German  Silver,  No.  439. 

Drawing  Pen,  No.  442. 

Do.  No.  444. 

Triangular  Scale,  6 inch “• 28  00 

The  following  sets  have  beautifully  finished  Mahogany  or  Walnut  Boxes, 

13  inches  long  by  6 inches  wide,  with  lock  and  key  and  tray. 

465. — Contains  pair  plain  Dividers,  No.  406. 

Set  of  Instruments,  No.  401. 

Steel  Bow  Pen,  No.  435. 

Drawing  Pen,  No.  442. 

Do.  No.  444. 

Triangular  Scale,  12  inch 20  00 


Price 


$25  00 


230 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


No.  Price 

466. — Contains  pair  plain  Dividers,  No.  406. 

Sets  of  Instruments,  Nos.  401  and  408. 

Steel  Bow  Pen,  No.  435. 

Steel  Bow  Pencil,  No.  437. 

Drawing  Pens,  Nos.  442  and  443. 

Triangular  Scale,  12  inch $26  50 

The  following  sets  have  beautifully  finished  Rosewood  Boxes,  13  inches 
long  by  7*  inches  wide,  with  lock  and  key  and  tray. 

467. — Contains  pair  plain  Dividers,  No.  406. 

Pair  Hair  Spring  Dividers,  No.  404. 

Sets  of  Instruments,  Nos.  401  and  408. 

Pair  Steel  Spacing  Dividers,  No.  433. 

Steel  Bow  Pen,  No.  435. 

Steel  Bow  Pencil,  No.  437. 

Drawing  Pens,  Nos.  442,  443,  and  444. 

Triangular  Scale,  12  inch 33  00 

468.  — Contains  pair  plain  Dividers,  No.  406. 

Pair  Hair  Spring  Dividers,  No.  404. 

Sets  of  Instruments,  Nos.  401  and  408. 

Proportional  Dividers,  No.  410. 

Steel  Spacing  Di  viders,  No.  433. 

Steel  Bow  Pen,  No.  435. 

Steel  Bow  Pencil,  No.  437. 

Drawing  Pens,  Nos.  442,  443,  and  444. 

Triangular  Scale,  12  inch 40  00 

469. — Contains  pair  plain  Dividers,  No.  406. 

Pair  Hair  Spring  Dividers,  No.  404. 

Sets  of  Instruments,  Nos.  401  and  408. 

Proportional  Dividers,  No.  411. 

Steel  Spacing  Dividers,  No.  433. 

Steel  Bow  Pen,  No.  435. 

Steel  Bow  Pencil,  No.  437. 

Beam  Compass,  No.  416. 

Drawing  Pens,  Nos.  442,  443,  and  444. 

Road  Pen,  No.  423. 

Dotting  Pen,  one  wheel,  No.  420. 

Triangular  Scale,  12  inch  57  00 

The  following  set  has  beautifully  finished  Rosewood  Box,  151  inches 
long  by  10  inches  wide,  with  lock  and  key  and  tray,  and  lined  with 
finest  silk  velvet. 

470. — Contains  pair  plain  Dividers,  No.  406. 

Pair  Hair  Spring  Dividers,  No.  404. 

Set  of  Instruments,  No.  400. 

Proportional  Dividers,  No.  413. 

Steel  Spacing  Dividers,  Nos.  432  and  433.  „ < 


No. 


W.  & L.  E.  GURLEY,  TROY,  N.  Y« 


231 , 

Price 


Beam  Compass,  No.  417. 

Steel  Bow  Pen,  No.  435. 

Set  of  Instruments,  No.  447. 

Steel  Bow  Pencil,  No.  437. 

Drawing  Pens,  Nos.  442,  443,  444. 

Road  Pen,  No.  422. 

Dotting  Pen  with  3 wheels,  No.  421. 

Protractor,  No.  623. 

Triangular  Scale,  12  inch. 

Set  of  Color  Cups,  No.  1587 $95  00 


ALTENEDER’S  PATENT  JOINT  DRAWING 
INSTRUMENTS. 


The  excellency  of  these  instruments  consists  in  the  joints  of  the  dividers 
being  so  constructed  as  to  prevent  any  irregular  motion  when  the 
legs  are  opened  or  closed,  also  for  the  general  care  with  which  the 
instruments  are  finished. 

All  the  pens  are  thoroughly  well  made  and  pointed.  No.  474  represents 
a sectional  view  of  Alteneder’s  Patent  Joint  Divider  head. 


475— Plain  Dividers  of  German  Silver,  3£  inches  long,  with  Alteneder’s  patent 

joint,  each $2  00 

476.— Plain  Dividers  of  German  Silver,  5 inches  long,  with  Alteneder’s  patent 

joint,  each , g 75 


232  W.  & L.  B.  GURLEY,  TROY,  N.  Y. 

No.  Price 

477. — Plain  Dividers  of  German  Silver,  6 inches  long,  with  Alteneder’s  patent 

joint,  each $3  25 

478. — Hair  Spring  Dividers  of  German  Silver,  3£  inches  long,  with  Alteneder’s 

patent  joint,  each 3 00 

479. — Hair  Spring  Dividers  of  German  Silver,  5 inches  long,  with  Alteneder’s 

patent  joint,  each 3 50 

480. — Hair  Spring  Dividers  of  German  Silver,  6 inches  long,  with  Alteneder’s 

patent  joint,  each 4 00 

481. — Needle  Point  Dividers,  3£  inches  long,  of  German  Silver,  with  Pencil 

Point  and  Alteneder’s  patent  joint,  each 4 25 

482. — Needle  Point  Dividers,  3£  inches  long,  of  German  Silver,  with  Pen  Point 

and  Alteneder’s  patent  joint,  each 4 75 

483. — Needle  Point  Dividers,  6 inches  long,  of  German  Silver,  with  Pen  and 

Pencil  Point  and  Lengthening  Bar,  and  Alteneder’s  patent  joint 7 50 

484. — Needle  Point  Dividers,  3^  inches  long,  of  German  Silver,  with  Pen  and 

Pencil  Point,  and  Alteneder’s  patent  joint 6 00 

485. — Steel  Point  Dividers,  6£  inches  long,  with  Pen,  Pencil,  Needle  Point  and 

Lengthening  Bar 8 50 

486. — Steel  Point  Dividers,  6£  inches  long,  with  Pen,  Pencil,  Needle  Point, 

Lengthening  Bar  and  joint  in  each  leg 11  00 

487. — Steel  Point  Dividers,  3|  inches  long,  with  Pen,  Pencil,  and  Needle  Point.  7 00 

488. — Steel  Spacing  Dividers,  3 inches  long 1 75 

489.  — Steel  Bow  Pen,  3 inches  long,  round  points 2 25 

490.  — “ u “ with  Needle  Point 2 75 

491. _  “ Pencil  “ with  round  point 2 25 

492.  — u “ “ with  Needle  Point 2 75 

493. — Drawing  Pen,  4\  inches  long 1 50 

494. —  “ 5J  “ 1 70 

495. —  w 6i  “ 1 90 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


233 


BRASS  DRAWING  INSTRUMENTS, 


FOR  SCHOOLS. 


500.  507.  509. 


No.  Price 

497.— Wood  Dividers,  13  in.  long,  with  crayon  holder,  for  black-board  drawing.  $1  00 


498. —  “ 16  “ “ u “ 1 25 

499. —  “ 20  “ “ “ “ 1 50 

500.  — Brass  Dividers,  3£  inches  long,  screw  joint 25 

501. —  “ 4*  “ “ 30 

502. —  “ 51  “ “ 85 

5a3.—  “ 6£  “ “ 45 

504. —  “ 4i  44  rivet  joint 20 

505. —  “ 5}  “ “ 25 

506. —  “ 6*  41  “ 80 

507. — Brass  Dividers,  inches  long,  with  Pen,  and  Pencil  Points  and  Length- 

ening Bar  ...  50 

508. — Brass  Dividers,  6 inches  long,  with  Pen  and  Pencil  Points  and  Length- 

ening Bar 75 

509. — Brass  Dividers,  Needle  Point,  4*  inches  long,  with  Pen  and  Pencil  Points 

and  Lengthening  Bar $ 75 

510. — Brass  Dividers,  Needle  Point,  6 inches  long,  with  Pen  and  Pencil  Points 

and  Lengthening  Bar 1 00 


234  W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


511.  612. 


513. 


514. 


No.  Price 

511. — Dividers,  brass,  medium  quality,  needle  point,  with  pen  and  pencil 

point,  3 inches $ 

512. — Bow  Pencil,  brass 

513. — Bow  Pen,  brass,  needle  points,  no  spring... 

514. — Bow  Pen,  brass,  needle  points,  and  adjusting  spring. . . 


515.  — Bisecting  Dividers,  brass 

516. — Proportional  Dividers,  brass,  divided  for  lines 2 

517.  — Drawing  Pen,  black  handle 

518. — Drawing  Pen,  ivory  handle 

519.  — Roulette  for  dotting  lines,  with  three  wheels 

520. — Double  Drawing  or  Road  Pen,  brass  mounted  . , 2 

521.  — Patent  Lead  Holder,  for  pencil  leg  of  Dividers 


W.  & L.  E.  GURLEY,  TROY,  Y.  235 

CASES  OF  BRASS  DRAWING  INSTRUMENTS. 

No.  Prick 

525. — Wood  Box;  pair  4^-inch  Dividers,  with  pen  and  pencil  points,  and 

Crayon  Holder $ 50 

526. — Wood  Box ; pair  4£-inch  Dividers,  with  pen  and  pencil  points  and  length- 

ening bar ; Ebony  handle  Drawing  Pen  ; Wood  Rule,  Crayon  Holder, 

and  Horn  Protractor 80 

52T. — Wood  Box;  Pair  of  4£-inch  Dividers,  with  pen  and  pencil  points  and 
lengthening  bar ; pair  of  3i-inch  plain  Dividers,  Drawing  Pen,  Horn 

Protractor,  W ood  Rule,  Crayon  Holder 1 00 

528.— Wood  Box;  Pair  5^-inch  Dividers,  with  pen  and  pencil  points  and 
lengthening  bar;  Pair  of  4^-inch  Plain  Dividers,  Drawing  Pen,  Horn 

Protractor,  Crayon  Holder,  and  Wood  Rule  1 30 

530. — Rosewood  Box  ; Pair  of  6-inch  Dividers,  with  pen  and  pencil  points  and 
lengthening  bar;  Pair  of  4i-inch  plain  Dividers,  Drawing  Pen  ; Pair  of 
3±-inch  Dividers,  with  pen  and  pencil  points ; Brass  Protractor,  Horn 
Protractor,  Wood  Rule 2 00 


530.  532. 


531.— Same  as  No.  530,  but  with  the  instruments  set  in  a tray,  so  that  colors, 

etc.,  may  be  put  below,  per  set |2  25 

532 — Rosewood  Box ; Pair  of  6-inch  needle-point  Dividers,  with  pen  and  pen- 
cil points,  and  lengthening-bar  ; Pair  44  inch  plain  Dividers  ; Pair  of 
3§-inch  needle-point  Dividers,  with  pen  and  pencil  points  ; Drawing 

Pen,  Brass  Protractor,  Horn  Protractor.  Wood  Rule,  per  set 2 75 

533. — Same  as  No.  532,  but  with  lock  and  key  and  the  instruments  set  in  a tray, 

so  that  the  colors  may  be  put  below,  per  set 3 00 


534.— Rosewood  Box,  with  lock  and  key,  the  instrnments  set  in  a tray,  so  that 
colors,  etc.,  may  be  put  below:  Pair  of  6-inch  needle-point  Dividers, 
with  pen  and  pencil  points,  and  lengthening-bar;  Drawing  Pen,  Pair 
41-inch  plain  Dividers,  Brass  Protractor.  Horn  Protractor.  Pair  of  3*- 
inch  needle-point  Dividers,  with  pen  and  pencil  points ; Spring  Bow 


Pen,  with  needle-point ; Wood  Rule 4 00 

535.— Same  as  No.  534,  with  addition  of  a pair  Proportional  Dividers,  has 

no  brass  Protractor,  but  has  wood  Triangle  and  Irregular  Curves 6 00 


236 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


FINE  GERMAN  SILVER  INSTRUMENTS. 


No.  Price 


540.  — Dividers,  German  Silver,  steel  joints,  turned  cheeks,  fine  finish,  4 inch.  $ 70 

541. —  “ “ “ “ “ 5 “ 

542. —  “ “ “ “ “ 6 “ . 1 

543. —  “ “ “ “ 7 “ . 1 

544. — Hair  Spring  Dividers,  German  Silver  ; steel  joints,  turned  cheeks,  fine 

finish,  5 inch 1 

645. —Hair  Spring  Dividers,  German  Silver ; steel  joints,  turned  cheeks,  fine 

finish,  6 inch 2 

547. — Dividers,  German  Silver ; fine  quality,  needle-point,  with  pen  and  pen- 

cil point,  4 inches  2 

548. — Dividers,  German  Silver;  fine  quality,  with  needle-point,  pen, lengthen- 

ing-bar, and  pencil-points,  6 inches 3 

549. — Dividers,  German  Silver ; 5 inch,  fine  finish,  with  sheath 1 

550. — Dividers,  German  Silver ; 5 inch,  three-legged 3 

554. — Proportional  Dividers,  German  Silver ; 7 inch,  with  points  bent  rectan- 

gular, for  Lines  and  Circles 7 

555. — Proportional  Dividers,  German  Silver,  6£  inches  long,  divided  for  lines.  2 

556. — Bisecting  Dividers,  German  Silver 1 

557.  — Spacing  Dividers,  all  steel,  with  Spring  and  Adjusting  Screw 1 

558. — Bow  Pen,  all  steel,  ivory  handle 1 

559. — Bow  Pencil,  all  steel,  ivory  handle 1 

560. — Set  of  three  Steel  Bows,  Pen,  Pencil,  and  Dividers,  in  case,  per  set 4 75 


S g 8 5 g 8 g g g g S $ 888 


W.  & L.  E.  GURLEY,  TROY,  N.  Y.  237 


555. 


No. 

561. — Spring  Bow  Pen,  German  Silver 

562. —  “ “ with  pencil-point 


Price 
•SI  62 
250 


563. 


No.  Price 

563.— Furniture  for  Beam  Compasses,  German  Silver,  with  adjusting  screw,  in 

morocco  case $5  oq 


238 


W.  & L.  E.  GURLEY,  TROY,  Y. 


564. 


No.  Price 

564. — Pocket  Dividers,  German  Silver,  folding  pen  and  pencil  points $5  50 

565. — Map  Perambulator  for  measuring  the  length  of  curved  lines,  rivers,  rail- 

roads, etc.,  on  maps,  each 1 50 


567.  568. 


571. 


566.  , 572.  574. 

566. — Improved  Bow  Pen.  The  needle-point  in  this  instrument  being  adjust- 

able, it  will  draw  extremely  minute  circles $3 

567. — Drawing  Pen,  German  Silver,  medium  finish 

568.  — Drawing  Pen,  German  Silver,  fine  finish,  hinge  to  pen 

569. — Drawing  Pen,  German  Silver,  fine  finish,  hinge  to  pen,  and  protracting 

pin 

570.  —Drawing  Pen,  all  German  Silver,  for  red  ink 

571.  — Double  Drawing,  or  Road  Pen 2 

572. —  Patent  Double  Drawing  Pen.  Will  draw  with  one  stroke  one  broad  or 

two  parallel  lines  of  the  same  or  different  widths 3 

573. — Drawing  Pen  for  curves 1 

574. —  Do.  for  heavy  border  lines  2 

575.  — Patent  Lead-holder,  for  pencil-leg  of  Dividers  (Fig.  521) 


sssss;  g a a sss 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


230 


CASES  OF  FINE  GERMAN  SILVER  INSTRUMENTS. 

FOR  ENGINEERS,  ARCHITECTS,  AND  MACHINISTS. 


No.  Price 

580. — Morocco  Box ; pair  of  5|-inch  dividers,  with  pen  and  pencil  points, 

drawing  pen $3  00 

581. — Morocco  Box;  pair  of  4 inch  dividers,  with  pen,  pencil,  and  needle 

points,  and  lengthening-bar,  drawing  pen 4 00 

58*2.-  Morocco  Box ; pair  of  5^-inch  dividers,  with  pen  and  pencil  points,  pair 

of  5-inch  plain  dividers,  drawing  pen 3 50 

583. — Same  as  No.  582,  with  addition  of  needle-points  and  lengthening-bar,  to 

5|-inch  dividers,  per  set . 5 00 

584. — Morocco  Box,  round  corners,  for  carrying  in  the  pocket ; pair  of  4|-inch 

dividers,  with  hinge  in  one  leg,  needle-points,  with  pen  and  pencil 
points,  and  lengthening-bar,  spring-bow  pen,  needle-point,  pair  of 
4- inch  plain  dividers,  rounded  point,  drawing  pen,  ivory  handle,  5-inch 
Ivory  rule,  divided  into  eighths,  per  set 7 50 


585.— Morocco  Box ; pair  of  5^-inch  dividers,  with  pen  and  pencil  points,  and 
lengthening-bar,  pair  of  5-inch  plain  Dividers,  pair  of  4-inch  dividers, 
with  pen  and  pencil  points,  drawing  pen,  German  silver  protractor, 
German  silver  square * $8  50 


240  W.  & L.  E.  GURLEY,  TROY,  H.  Y. 


points,  and  lengthening-bar,  pair  of  5-inch  plain  dividers,  spring-bow 
pen,  drawing  pen $6  50 

587. — Morocco  Box ; pair  of  5^-inch  dividers,  with  pen,  pencil,  and  needle 

points,  and  lengthening-bar,  pair  of  5-inch  plain  dividers,  pair  of 
4-inch  dividers,  with  pen,  pencil,  and  needle  point,  2 drawing  pens, 
per  set 9 75 

588. — Same  instruments  as  in  No.  587,  with  addition  of  spring  bow-pen,  per  set  11  00 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


241 


No.  Price 

589. — “R.  P.  I.”  Polished  Mahogany  or  Walnut  Box,  with  lock  and  key  and 

tray,  containing  pair  5i-inch  dividers,  pen,  pencil,  and  needle  point, 
pair  5-inch  hair-spring  dividers,  pair  4-inch  dividers,  pen,  pencil,  and 
needle  point,  2 Swiss  pens,  Nos.  442  and  444 $14  00 

590.  — Polished  Mahogany  or  Walnut  Box;  containing  pair  5^-inch  dividers, 

with  pen,  pencil  and  needle  points,  and  lengthening-bar, 

Pair  5-inch  plain  Dividers, 

Pair  of  4-inch  Dividers,  with  pen,  pencil,  and  needle  points, 


Spring  Bow  Pen,  with  needle-point, 

2 Drawing  Pens, 

German  Silver  or  Rubber  Square, 

German  Silver  Protractor 12  50 

591.— Same  as  No.  590,  with  lock  and  key  and  tray 13  50 


592.— Polished  Mahogany  or  Walnut  Box;  containing  5|-inch  dividers,  with 
pen,  pencil,  and  needle  point,  and  lengthening-bar, 

Pair  of  5 inch  plain  Dividers, 

Pair  of  5-inch  Hair  Spring  Dividers, 

Pair  of  4-inch  Dividers,  with  pen,  pencil,  and  needle  points, 

Spring  Bow  Pen,  with  needle-point, 

2 Drawing  Pens, 

German  Silver  or  Rubber  Square, 


German  Silver  Protractor 15  00 

593.— Same  as  No.  592,  and  the  box  much  larger,  with  lock  and  key  and  tray 

thus  affording  space  for  extra  instruments  or  colors,  etc 15  50 


594.— Polished  Mahogany  or  Walnut  Box,  with  lock  and  key  and  tray ; con- 
taining pair  6-inch  dividers,  with  pen,  pencil,  and  needle  point,  and 
lengthening-bar, 

Pair  5-inch  plain  Dividers, 

Pair  5-inch  Hair  Spring  Dividers, 

Pair  4-inch  Dividers,  with  pen,  pencil,  and  needle  point, 

Bow  Pen,  German  Silver, 

2 Drawing  Pens, 

1 Red  Ink  Pen,  1 Road  Pen, 

Pair  Proportional  Dividers,  No.  555, 

Protractor,  4-inch,  half  circle,  whole  degrees, 

Triangle  and  Triangular  Scale,  12-inch % 00 

695.— Same  as  No.  594,  with  addition  of  Beam  Compass 31  00 


242 


w.  & L.  E.  GURLEY,  TROY,  K.  Y. 


No.  Price 

596.— Polished  Mahogany  or  Walnut  Box,  lock  and  key,  with  tray,  leaving 
space  below  for  paints,  rules,  etc.,  containing  pair  of  6-inch  needle- 
point dividers,  with  pen  and  pencil  points,  and  lengthening-bar, 

Pair  4^ -inch  plain  Dividers, 

Pair  of  4-inch  Needle  Point  Dividers,  with  pen  and  pencil  points, 

Pair  of  Proportional  Dividers, 

3 Drawing  Pens, 

Horn  Protractor, 

1 Wood  Curve  and  2 Wood  Squares, 

Bow  Pen,  German  Silver,1 

Ivory  Protractor  Scale $27  00 


597. — Polished  Mahogany  or  Walnut  Box,  lock  and  key,  with  tray,  leaving 
space  below  for  paints,  rules,  etc. ; containing  pair  of  6-inch  needle- 
point dividers,  with  pen  and  pencil  points  and  lengthening-bar, 

Pair  4^-inch  plain  Dividers, 

Pair  of  4-inch  Dividers,  needle-point,  with  pen  and  pencil  points, 

Pair  of  Proportional  Dividers, 

Bow  Pen,  needle-point, 

3 Drawing  Pens, 

Furniture  for  Beam  Compass,  with  Micrometer  Screw, 

8-inch  Horn  Protractor, 

Ivory  Protractor  Scale 


34  00 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


243 


EXTRA  FINE  GERMAN  SILVER  SWISS  PROTRACTORS. 


No.  Price 

600. —  Protractor,  4-inch  diameter,  half  circle,  whole  degrees,  centre  on  outer 

edge $1  50 

601. — Protractor,  5-inch  diameter,  half  circle,  half  degrees,  centre  on  outer 

edge 2 00 

602. — Protractor,  6-inch  diameter,  half  circle,  half  degrees,  centre  on  outer 

edge 3 00 

603. — Protractor,  6-inch  diameter,  half  circle,  quarter  degrees,  centre  on  outer 

edge 3 25 


604  — Protractor,  5 inch  diameter,  half  circle,  half  degrees,  centre  on  inner 

edge $2  50 

605. - Protractor,  6-inch  diameter,  half  circle,  half  degrees,  centre  on  inner 

edge 3 50 

606. — Protractor,  6-inch  diameter,  half  circle,  quarter  degrees,  centre  on  inner 

edge 4 00 


244 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


EXTRA  FINE  SWISS  PROTRACTORS,  OF  GERMAN 
SILVER,  WITH  ARMS. 


No.  Price 

611.— German  Silver  Protractor,  6 inches  diameter,  half  circle,  with  arm,  and 

divided  in  half  degrees $8  50 

613. — German  Silver  Protractor,  8 inches  diameter,  half  circle,  with  arm,  and 

divided  in  half  degrees ...  9 50 

614. — German  Silver  Protractor,  5 inches  diameter,  whole  circle,  with  arm,  and 

divided  in  half  degrees 9 00 

615. — German  Silver  Protractor,  6 inches  diameter,  whole  circle,  with  arm,  and 

divided  in  half  degrees $10  00 

EXTRA  FINE  SWISS  PROTRACTORS,  OF  GERMAN 
SILVER,  WITH  ARMS  AND  VERNIERS. 


620. — Protractor,  5£  inches  diameter,  half  circle,  half  degrees,  with  vernier 

reading  to  three  minutes $11  00 

621. — Protractor,  8 inches  diameter,  half  circle,  quarter  degrees,  with  vernier 

reading  to  one  minute 14  00 

622. — Protractor,  10  inches  diameter,  half  circle,  quarter  degrees,  with  vernier 

reading  to  one  minute 18  00 

623. — Protractor,  5£  inches  diameter,  whole  circle,  half  degrees,  with  vernier 

reading  to  three  minutes . 14  50 

624. — Protractor,  8 inches  diameter,  Whole  circle,  quarter  degrees,  with  ver- 

nier reading  to  one  minute 16  00 

Cases  for  Protractors,  of  wood,  lined  with  velvet,  according  to 
size  : from  $1  00  to  $3  00. 


W.  & L.  E.  GURLEY.  TROY,  N.  Y.  245 

PROTRACTORS  OE  HORN,  BRASS,  GERMAN  SILVER, 
RUBBER,  IVORY  AND  PAPER. 

No.  Price 

630. — Railroad  Curve  Protractor,  of  horn,  8 inches  diameter,  having  laid  off  on 

it  twenty-three  curves  from  \ degree  to  8 degrees,  with  a radius  of  400 
feet  to  the  inch $1  60 

631. — Horn  Protractor,  5 inches  diameter,  whole  circle,  half  degrees 1 00 

632. —  “ 6 “ “ “ 1 25 

633. -  “ 7 “ “ “ 1 50 

634.  — u 4 44  half  circle,  whole  degrees 15 


635.— Horn  Protractor,  5 inches  diameter,  half  circle,  half  degrees 


636.-  “ 6 

44 

“ 

637.—  “ 7 

44 

u 

638.-  “ 8 

44 

44 

44 

639.— Brass  Protractor,  4 

44 

44 

whole  degre 

640.-  “ 4 

44 

44 

half  degrees , 

641.—  “ 5 

44 

44 

“ 

642.—  “ 6 

44 

44 

44 

643.— German  Silver  Protractor,  4 inches  diameter,  half  circle,  whole  degrees. . 


644.- 

44 

5 

44  half  degrees 

645.- 

“ 

6 

“ 

646.—  “ 

u 

7 

it  it 

647.- 

“ 

5 

44  beveled  edge,  half  deg. 

648.— 

“ 

6 

“ 44 

649.— 

“ 

7 

44 

650.— Hard  Rubber 

Protractor, 

6 

“ 

651.- 

44 

8 

44  44  44 

652.- 

44 

6 

whole  circle,44  44 

653.- 

“ • 

8 

“ 44  44 

$ 25 
30 
50 
80 
10 
35 
55 
65 
50 
85 
1 00 
1 15 

1 25 

2 00 

2 65 

3 00 
3 75 
3 75 
5 00 


Other  sizes  and  graduations  to  order. 


246 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 

PAPER  PROTRACTORS. 


No-  Price 

655. — Whole  Circle  Protractors,  8 and  13  inches  diameter,  half  degrees,  on 

drawing  paper,  each g 39 

656. — Whole  Circle  Protractors,  8 and  13  inches  diameter,  half  degrees,  on 

Bristol  board,  each 

657. — Half  Circle  Protractor,  5 inches  diameter,  half  degrees,  card  board 

658. — Half  Circle  Protractor,  6 inches  diameter,  half  degrees,  card  board 

659. — Circular  Protractor  on  tracing  paper,  14  inches  diameter,  quarter  degrees 

(these  are  used  by  the  U.  S.  Coast  Survey,  and  U.  S.  Navy,  and  give 
entire  satisfaction) 25 


CROZET’S  PROTRACTOR. 

660. — Eight  inches  diameter,  vernier  reading  to  one  minute,  German  'silver, 

in  case,  price $40  00 

The  Crozet  Protractor,  named  from  its  inventor,  an  officer  of  the  U.  S. 
Engineer  Corps,  we  recommend  as  the  best  among  the  various  high 
grade  protractors  yet  devised. 

It  may  be  used  with  the  T rule  or  straight  edge.  The  feather  edge  is 
always  set  to  the  starting  point  and  the  line  produced  without  punc- 
turing the  paper. 

The  feather  edge  is  the  only  metallic  bearing  upon  the  paper,  small  ivory 
projections  on  the  under  side  of  the  frame  keep  the  metal  from  con- 
tact with  the  paper  and  prevent  soiling  it* 


^ O*  CO 


W.  & L.  E.  GURLEY,  TROY,  N.  Y, 


247 


NEW  LIMB  PROTRACTOR. 

BRONZE  HEAD,  STEEL  BLADE,  VERNIER  TO  ONE  MINUTE. 


665.— Limb  Protractor,  blade  24  inches  long, 


666~  “ “ 30  “ 8 75 

667  — “ “ 36  “ 9 50 

668‘~  • “ “ 42  “ 10  25 

669~~  “ “ 48  “ 11  00 


If  with  nickel-plated  blades,  50  cts.  to  75  cts.  extra.  Longer  blades 
made  to  order. 


248 


W.  * L.  E.  GURLEY,  TROY,  N.  Y. 


IVORY  PROTRACTORS. 


675. — Ivory  Rectangular  Protractor,  6 inches  long,  inches  wide,  with  scales 

as  follows  : front  sides  divided  around  edges  from  0 to  180  degrees  in 
single  degrees,  scales  of  34,  14,  % and  1 inch  to  the  foot,  and  scale  of 
chords.  Reverse  side  scales  of  30,  35,  40,  45,  50  and  60  parts  to  the 
inch,  scale  of  chords  and  diagonal  scale  of  inches  and  T£5ths $1  50 

676. — Ivory  Rectangular  Protractor,  6 inches  long  by  1%  inches  wide,  with 

scales  as  follows  : front  side,  the  edge  divided  in  single  degrees  from 
0 to  180  degrees,  scales  of  %,  14,  %,  34,  %,  %,  %,  and  1 inch  to  the  foot, 
and  scale  of  chords.  On  the  reverse  side,  scales  of  30,  35,  40,  45,  50 
and  60  parts  to  the  inch,  scale  of  chords  and  diagonal  scale  of  T£oths. . . 2 25 

677.  — Ivory  Rectangular  Protractor,  6 inches  long  by  2 inches  wide,  with  scales 

as  follows : front  side,  the  edge  divided  in  single  degrees  from  0 to 
180  degrees,  scales  of  34,  34,  %,  >4,  %,  %,  %,  1,  134, 1)4  inches  to  the 
foot,  scale  of  chords,  and  line  of  40  parts  on  lower  edge.  On  the  re- 
verse side,  scales  of  20,  25,  30,  35,  40,  45,  50,  60  parts  to  the  inch,  diag- 


onal scale  of  rAoths 3 25 

678. — Ivory  Rectangular  Protractor,  same  as  No.  677,  but  has  the  Protractor 

divided  in  X degrees 4 00 


679 —Ivory  Rectangular  Protractor,  6 inches  long  by  234  inches  wide,  with 
scales  as  follows : front  side,  the  edge  divided  in  34  degrees  from  0 to 
180  degrees,  scales  of  %,  34,  34,  34,  34,  34,  34,  1,  1/4,  134?  134,  134  inches 
to  the  foot,  scale  of  chords,  and  scale  of  40  parts  on  the  lower  edge.  Re- 
verse side,  scales  of  10,  15,  20,  25,  30,  35,  40,  45,  50,  60  parts  to  the  inch, 
and  diagonal  scale  of  TT5ths 4 50 

680. — Ivory  Rectangular  Protractor,  6 inches  long  by  234  inches  wide,  with 

scales  as  follows,  front  side,  the  edge  divided  in  34  degrees  from  0 to 
180  degrees,  scales  of  34,  34,  34,  34,  34,  %>  1,  1)4, 134, 134, 134  inches 
to  the  foot,  scale  of  chords,  and  scale  of  40  parts  on  lower  edge.  Re- 
verse side,  scales  of  20,  25,  30,  35,  40,  45,  50  and  60  parts  to  the  inch,  2 
scales  of  chords,  scales  of  latitude,  sines,  tangents,  hours,  longitudes, 
secants,  rhombs 6 00 

681. — Ivory  Rectangular  Protractor,  8 inches  long  by  2 inches  wide,  with  scales 

as  follows  : front  side,  the  edge  divided  in  34  degrees  from  0 to  180  de- 
grees, scales  of  34, 34,  .34, 34,  34,  34,  34,  1 inch  to  the  foot,  scale  of  chords 
and  scale  of  40  parts  on  lower  edge.  Reverse  side,  scales  of  30,  35,  40. 

45,  50,  60  parts  to  the  inch,  scale  of  chords  and  diagonal  scale  of  r^ths.  5 00 


w.  & L.  E.  GURLEY,  TROY,  N.  Y. 


249 


No. 


Price 


682  —Ivory  Rectangular  Protractor,  12  inches  long  by  2K  inches  wide,  with 
scales  as  follows:  the  edge  divided  in  X degrees  from  0 to  180  degrees, 
scales  of  X,  M,  X,  X,  X,  K,  %■  h IX,  IX,  IX,  IX,  scale  of  chords 


scales  oi  78>  7*1  /■*»  0rt 

and  scale  of  40  on  lower  edge.  Reverse  side,  scales  of  10, 15,  20,  25,  30, 
35,  40,  45,  50,  60  parts  to  the  inch,  scale  of  chords  and  diagonal  scale  of 


Tooths  . 


$11  50 


IVORY  SECTORS  AND  SCALES. 


685— Ivory  Sector,  6 inches  long,  opens  to  12  inches  long 

686. — Ivory  Scale,  6 inches  long,  for  school  drawing 

687. — Flat  Ivory  Scale,  6 inch,  divided  %,  1 inch  t0  tlie  fo°L  each 

688. —  Do.  do.  12  do.  %,  34,  >£,  1 do.  do. 

689. —  Do.  do.  12  do.  %,  %,  llA,  3 do.  do. 


IVORY  CHAIN  SCALES. 


690. 


690.  —Ivory  Chain  Scales,  12  inches  long,  graduated  on  two  edges  with  either 
10  and  10  parts,  or  10  and  20,  or  20  and  40,  or  30  and  50,  or  40  and  60, 


or  50  and  60,  each $3 

691. —  Do.  with  40  and  80,  or  50  and  100,  each 5 

692. —  Do.  with  80  and  100,  each 5 75 

692A. — Ivory  Off-set  Scales,  2 inches  long,  10  by  10,  10  by  20,  20  by  40,  30  by 

50,  40  by  60,  each  65 


ARCHITECTS’  IVORY  SCALES. 


693.— Ivory  Scale,  12  inches  long,  with  16  scales,  as  follows : bH, 

Ht  %» 1, 13^,  1%,  1%,  2,  23£,  214  and  3 inches  to  the  foot,  the  first 
division  of  each  scale  subdivided  in  12  parts,  each $3  00 


8 8 8 8 8 


250 


W.  & L.  E.  GURLEY,  TROY,  K.  Y. 


"0*  Price 

694. — Same  as  No.  693,  but  with  the  first  division  of  each  scale  subdivided  into 

10  parts,  each 3 qq 

695. — Ivory  Scale,  12  inches  long,  with  12  scales,  as  follows  : Tsff,  1 4,  %, 

L 1^4 1 2 and  3 inches  to  the  foot,  the  first  division  of  each 

scale  subdivided  into  12  parts,  diagonal  scale  reading  to  T£5  and  2&0  of 
an  inch,  each ; 3 qq 

696. — Same  as  No.  695,  but  has  the  first  division  of  each  scale  subdivided  into 

10  parts,  each 3 qq 

697— Ivory  Scale,  12  inches  long,  one  side  rounded,  the  other  flat,  with  the 


following  scales,  the  graduations  of  which  are  all  brought  to  the  edge : 
re,  X,  A,  k U & %>  L lfc,  U/2,  1%,  2,  2 % and  3 inches  to 

the  foot,  the  first  division  of  each  scale  is  subdivided  into  twelve  parts, 
each 3 qq 

698.— Same  as  No.  697,  but  the  first  division  of  each  scale  subdivided  into  ten 

parts,  each 3 qq 


BOXWOOD  SCALES  AND  PROTRACTORS. 


700.  -Boxwood  Protractor,  6 inches  long,  inches  wide,  whole  degrees,  with 


6 scales  of  equal  parts,  4 scales  of  feet  and  inches,  2 scales  of  chords, 
and  diagonal  scale $0 

701. — Boxwood  Scale,  6 inches  long,  same  as  in  School  Cases  of  Instruments. . 

702. — Flat  Boxwood  Scale,  6 inch,  divided  %,  }£,  1 or  %,  1*4,  3 inch  to 

the  foot,  each 75 

703. — Flat  Boxwood  Scale,  12  inch,  divided  yz,  H,  1 or  %■>  iy2,  3 inch  to 

the  foot,  each 1 25 

704. — Flat  Boxwood  Scale,  24  inch,  divided  %,  14,  1 or  %,  %,  ll/2>  3 inch  to 

the  foot,  each 2 50 

705. — Flat  Boxwood  Scale,  12  inch,  beveled  on  both  sides,  graduated  % , 14, 

1 and  %,  1X>  3 inch  to  the  foot,  each 1 50 


BOXWOOD  CHAIN  SCALES. 


706 


SB 


W.  & L.  E.  GtTRLEY,  TROY,  N.  Yc 


251 


No.  Price 

706. — Boxwood  Chain  Scales,  12  inches  long,  graduated  on  two  edges  with 

either  10  and  10  parts,  or  10  and  20,  or  20  and  40,  or  30  and  50,  or  40  and 
60,  or  50  and  60 $1  25 

707. — Boxwood  Off-set  Scales,  2 inches  long,  graduated  10  by  10, 10  by  20,  20 

by  40,  30  by  50,  40  by  60,  each 25 


ARCHITECTS’  BOXWOOD  SCALES. 


708. 


708.— Boxwood  Scale,  12  inches  long,  with  16  scales,  as  follows  : y8,  T3g,  14,  %, 
34,  %,  1>  134,  114,  1M>  2,  2K,  2 yz  and  3 inches  to  the  foot,  the 


first  division  of  each  scale  subdivided  into  12  parts,  each $1  25 

709,—Same  as  No.  708,  but  with  the  first  division  of  each  scale  subdivided 

into  ten  parts,  each  1 25 


710. — Boxwood  Scale,  12  inches  long,  with  12  scales,  as  follows : %, 

%,  1,  IX,  134, 1%,  2 and  3 inches  to  the  foot,  the  first  division  of  each 
scale  subdivided  into  12  parts,  and  diagonal  scale  reading  to  Tho  and 
of  an  inch,  each 1 

711. — Same  as  No.  710,  but  has  the  first  division  of  each  scale  subdivided  into 

125 

712. — Boxwood  Scale,  12  inches  long,  one  side  rounded,  the  other  flat,  with 

the  following  scales,  the  graduations  of  which  are  all  brought  to  the 
edge : X,  A,  34,  X,  X,  X,  X,  t IX,  U4,  IX.  W and  3 inches  to 

the  foot,  the  first  division  of  each  scale  subdivided  into  12  parts,  each. . 1 25 

713. — Same  as  No.  712,  but  has  the  first  division  of  each  scale  subdivided  into 


10  parts,  each  1 25 

715. — Boxwood  Gunter  Scales,  12  inches  long 

716. —  do  do  24  do  1 25 

717. — Boxwood  School  Rule,  12  inches,  % and  TV  inch 15 

718. -  do  do  18  do  do  50 


252 


W.  & L.  E.  GURLEY,  TROY,  H.  Y. 


FLAT  METALLIC  CHAIN  SCALES. 

(A  new  and  superior  article,  our  own  make,  made  of  brass  and  silver-plated.) 


No.  Price 

719.— Flat  Metallic  Chain  Scale,  12  inches  long,  graduated  on  two  beveled 

edges,  10  and  20,  or  20  and  40  parts  to  the  inch,  each $3  00 

719A.—  Do.  with  30  and  50,  or  40  and  60  parts,  each 3 75 

719B. — Do.  with  50  and  60,  or  40  and  80  parts,  each 4 25 

719C. — Do.  with  50  and  100,  or  80  and  100  parts,  each 5 00 

719H. — Do.  30  centimetres  long,  divided  to  millimetres 3 00 


TRIANGULAR  SCALES  OF  BOXWOOD  AND  METAL. 


m 


No.  Price 

720.  — Triangular  Scale  of  Boxwood,  24  inches  long,  graduated  10,  20, 30, 40,50, 

and  60  to  the  inch $5 

721. -  Do.  20,  30,  40,  50,  60,  and  80  to  the  inch 5 

722. — Triangular  Scale  of  Boxwood,  12  inches  long,  graduated  same  as  No.  720.  2 

723.  — Do.  graduated  same  as  No.  721 2 

724.  — Do.  12  inches  long,  graduated  100,  290,  300,  400,  500,  600  to  the 

foot  each 2 

725.  — Do.  6 inches,  graduated  same  as  Nos.  720  or  721 1 

726.  — Triangular  Scale  of  Boxwood  for  Off-sets,  2 inches  long,  10,  20,  30,  40, 

50  and  60  parts 

727. — Triangular  Scale  of  Boxwood,  24  inches  long,  graduated  &,  Tso,  %,  *4, 

%,  14,  %,  1,  ly2,  and  3 inches  to  the  foot,  and  16ths  of  inches 5 


728. —  Do.  12  inches  long 2 

729. —  Do.  6 inches  long 1 


We  desire  to  call  the  attention  of  Draughtsmen  to  the  new  Patent  Me- 
tallic Triangular  Scales,  which  are  of  the  exact  size  and  shape  of  the 
common  12-inch  Triangular  Boxwood  Scales.  They  are  made  from 
brass  tubing  with  the  ends  closed,  nickeled  with  a dull  finish,  and 
weigh  less  than  three  and  one-half  ounces 
The  liability  of  the  wood  scales  to  crack,  warp  or  twist,  the  chipping 
of  their  edges,  and  their  variation  from  standard  measurement,  are 
well  known  to  all  who  have  used  them.  These  objections  have  been 


overcome  in  the  new  scale. 

730. — Metallic  Triangular  Scale,  12  inches,  graduated  same  as  No.  720  3 

731. —  Do.  do.  do.  No.  721 3 

732  — Do.  do.  do.  No.  727 3 

733.— Guard  for  Triangular  Scale,  white  metal.  The  use  of  this  Guard,  pre- 
vents all  errors 25 


88S  g 8 § ct  S8  8888 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


253 


PAPER  SCALES. 

No.  Price 

735. — Paper  Scale,  printed  on  card-paper,  IX  inch  wide,  12  inches  long,  gradu- 

ations on  one  edge  inches  and  lOths,  and  the  other  feet  and  lOOths $ 10 

736. —  Paper  Scale,  same  as  735,  edges  20  and  40  parts  to  the  inch 10 

737. — Paper  Scale,  same  as  735,  edges  16  and  48  parts  to  the  inch 10 


Paper  Scales,  printed  on  card-paper,  19  inches  long,  for  architects  and 
engineers,  as  follows : 

738. — Series  A contains  6 scales,  one  each  divided  to  14,  y2,  %,  1, 1>£,  and  3 


inches  to  the  foot,  per  set $1  00 

739. — Series  B contains  6 scales,  one  each  divided  to  gS2,  r3e,  Tse,  and  % 

inches  to  the  foot,  per  set 1 CO 

740. — Series  C contains  6 scales,  one  each  divided  to  10,  20,  30,  40,  50,  and  60 

parts  to  the  inch,  per  set 1 00 

Single  Scale  of  any  of  the  above  series,  A,  B,  C— each  scale 20 

The  advantages  of  these  scales  are— they  expand  and  contract  nearly  the 
same  as  drawing-paper,  do  not  soil  the  work,  and  distances  can  be  set 
off  from  them  without  the  use  of  dividers. 

We  manufacture,  to  order,  scales  to  any  divisions,  in  Ivory,  Boxwood, 
Rubber,  or  Metal. 


METRIC  SCALES  AND  RULES. 


741. — Flat  Boxwood,  fully  divided,  10  centimetres  long $ 60 

742. —  Do.  do.  20  do.  ...  90 

743. -  Do.  do.  30  do 1 25 

744. —  Do.  do.  50  do.  1 75 

745— Flat  Ivory,  do.  10  do.  2 25 

746.  — Do.  do.  20  do.  4 00 

747. -  Do.  do.  30  do.  5 00 

748. — Triangular  Boxwood, do.  20  do.  1 50 

749. —  Do.  do.  30  do.  2 00 

750.  -Metric  Rule,  boxwood,  1 metre,  6 fold,  with  springs  at  each  joint 75 

751. —  Do.  do.  4 fold,  divided  inches  and  metre 60 

752. — Same  as  above,  but  in  ivory 1 75 

753.  — Do.  do.  and  only  y2  m.  in  length 1 00 

754.  — Engineers’  Metric  Rule,  4 foot,  8 fold,  divided  to  inches  and  meters 75 


254 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


No. 

755.  — 1 

756. -2 

757. -3 

758. -4 

759. -6 

760. — 9 


STANDARD  STEEL  RULES. 


Price 

$ 25 

761.— 12  inch 

40 

762.— 18  “ 

50 

763.-24  “ 

75 

764.-36  “ 

1 00 

1 50 

765.-48  “ 

The  rules  in  this  list  are  divided  five  ways  in  parts  of  inches  as  follows : 


No.  1 Graduations . 
1st  cor.  10,  20,  50,  100 
2d  cor.  12,  24,  48 
3d  cor.  16,  32,  64 
4th  cor.  14,  28 


No.  2 Graduations. 
10,  20,  50,  100 
12,  24,  48 
16,  32,  64 

8 


No.  3 Graduations. 
16,  32,  64 
16 
16 
8 


No.  4 Graduations. 
1st  cor.  64 
2d  cor.  32 
3d  cor.  16 
4th  cor.  8 


No.  6 Graduations. 

1st  cor.  32  whole  length. 
2d  cor.  48  “ 

8d  cor.  50  “ 

4th  cor.  64  “ 


766. — 12  in.  Steel  Rule  of  No.  5 graduation $3  00 

767. -24  in.  “ “ 6 00 


No.  5 Graduations. 

1st  cor.  16,  32,  64 

2d  cor.  11,  14,  15,  17,  18, 19,  20,  21,  22,  23,  24,  25 

3d  cor.  26,  27,  28,  29,  30,  31,  33,  34,  35,  36,  37,  38 

4th  cor.  39,  40,  41,  42,  43,  44,  45,  46,  47,  48,  49,  50,  100 

Always  give  graduation  when  ordering  these  goods. 

770.— 36-inch  Steel  or  Standard  Yard,  full  divided $3  00 


STANDARD  STEEL  RULES.  FRENCH  MEASURE. 


773.  — 2V  metre $ 45 

774.  — iV  “ 85 

775.  — l “ 1 75 


776.  — *0  metre $2  50 

777. -1/2  “ 4 00 

778. —  “ 10  00 


They  are  divided  on  three  edges  to  millimetres,  and  on  one  edge  to  fifths 
of  millimetres. 


W.  & L.  £.  GURLEY,  TROY,  N.  Y. 


255 


TRIANGULAR  STEEL  RULES. 


No. 

780. — 3 inch 

781. -4  “ 


780. 

$ 60  I 782  —6  inch. 
80  I 783.-12  “ 


Price 

$1 

3 


Graduations. 

16,  64, 100  to  the  inch  whole  length. 

16,32,  64 

20,  50, 100,-12,  24,  48,-16,  32,  64  to  the  inch. 

The  12  in.  are  divided  only  as  follows  : 8, 10,  12,  14, 16,  20,  24,  28,  48,  50, 
64,  100  to  the  inch. 


SQUARE  STEEL  RULES. 


785. 


$ 50  I 787.-6  inch $1 

75  I 

Graduations. 

8, 16,  32,  64  to  the  inch  whole  length. 

16, 32, 64, 100  “ “ 

16,  64,  50, 100 


STANDARD  STEEL  STRAIGHT  EDGES. 

Of  same  width  and  thickness  as  Standard  Rules. 

790. — 18  inch $2  25  I 792.-36  inch $6 

791. -24  “ 3 00  I 793.-48  “ 9 


785. -3  iuch 

786. -4  “ 


STEEL  STRAIGHT  EDGES. 


FOR  DRAUGHTSMEN. 


800. — 15  inch $ 90 

801. -18  “ 1 00 

802. — 24  “ 1 50 

803. — 30  “ 2 25 


804. — 36  inch $3 

805. -42  “ 3 

806. -48  “ 5 

807. -60  “ 7 


We  also  furnish  Nos.  790  to  807.  Nickel  Plated,  at  an  extra  cost  of  25cts. 
to  $1  50,  according  to  length. 


S3  S 88  8 “ 8 8 


256 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


STEEL  AND  GERMAN  SILVER  TRIANGLES  AND 
SQUARES. 


— h 

824. 


Price 
$4  25 


$4  25 


OPEN  GERMAN  SILVER  TRIANGLES. 

30°  x 60°  x 90°. 

815. — 6 inch $2  50  I 817.— 10  inch 

816. -8  “ 3 00  I 818.-12  w 

45°  X 45°  x 90°. 

820. -5  inch $2  25  I 822.-8  inch 

821. -6  u 2 75  I 823.— 10  “ 

Other  sizes  of  Steel  and  German  Silver  Triangles  made  to  order 
824.— German  Silver  Squares,  perpendicular  5 to  6 inches 


$4 
5 

$4 
5 

$ 75 


OPEN  STEEL  TRIANGLES. 

30°  x 60°  x 90°. 

No. 

810.— 6 inch $3  25  j 811. — 10  inch 

45°  x 45°  x 90°. 

812.— 5 inch $3  25  | 813.— 8 inch 

For  Nos.  810  to  813,  if  Nickel  Plated,  add  50  cts.  each. 


88  © 8 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


257 


STRAIGHT  EDGES,  OF  RUBBER  AND  WOOD. 

(For  steel  straight  edges , see  Nos.  790  to  807. 


Hard  Rubier  Straight  Edges , one  edge  leveled . 

No.  Price 

825.-18  inch $ 70  828.— 36  inch $2  00 


8?6  -24 
827.— 30 


$ 70 
1 00 
1 50 


828. -36  inch . 

829. -42  “ . 

830. -60  “ . 


2 


Hardwood  Straight  Edges , one  edge  leveled . 


835. — 18  inch $ 25 

836. -24  “ 30 

837. — 30  “ 40 

838. -36  “ 50 


839.  — 42  inch. 

840. -48  “ . 

841. — 60  u . 

842. -72  “ . 


Polished  Rosewood , Satin  wood,  or  Mahogany  Straight 
Edges,  one  edge  leveled . 


846  — 24  inch $ 75 

847. -30  “ 1 00 

848. -36  “ 1 25 


849. -42  inch. 

850.  — 48  “ . 

851. — 60  “ . 


$1 

2 

2 


Other  lengths  made  to  order. 


Cross  Section  Triangles . 


HARD  RUBBER. 


855. 


855.— Cross  Section  Triangles,  set  of  seven  Cross  Section  Triangles  made  of 
hard  rubber  as  follows : % to  1,  X to  1,  % to  1,  1 to  1,  \}£  to  1,  ly2  to  1, 

2 to  1,  per  set $3 

Single  Triangles  of  set  No.  855,  each 


SS  g 8 § S8s!8i  gg 


258 


W.  & L.  E.  GURLEY,  TROY,  N.  Y, 


TRIANGLES. 


RUBBER,  ROSEWOOD,  SATINWOOD,  OR  HARDWOOD. 

{For  Steel  and  German  Silver  Triangles , see  Nos.  810  to  823.) 


boa.  875. 


Hard  Rubier  Triangles , 

No. 

860. — 3 inch $ 

861. -4  “ 


863. -6  “ 

864. -7  “ 

865. -8  “ 

866. -9  “ 


angles  30,  60,  and  90  degrees. 


25 

25 

30 

35 

40 

55 

60 


Price 


867. — 10  inch .$  65 

868. -11  “ 75 

869. — 12  “ 95 

870. -13  “ 1 10 

871. -14  “ 1 

872. -15  “ 1 

873. -16  “ 1 75 


Hard  Rubber  Trianglesy  angles  45,  45,  and  90  degrees. 


875. — 3 inch $ 30 

876. -4  “ 35 

877. -5  “ 40 

878. -6  “ 50 

879. -7  “ 60 

880. — 8 “ 70 


882.— 10  inch 

$1  10 

883.-11  “ 

1 25 

884.— 12  “ 

1 35 

885.— 13  “ 

1 50 

886  14  “ 

, . , , . 1 65 

887.— 15  “ 

8 8 


W.  & L.  E.  GURLEY,  TROY,  X.  Y. 


250 


No.  Price 

890.— Hard  Rubber  Lettering  Triangles,  3 in  set,  Sl/2  inch,  per  set $1 

Single  Templets 


Rosewood , Satimvood , and  Hardwood  Triangles . 


Rosewood  or  Satimvood , centre , Framed . 

30°  x 60°  x 90°. 

900. — 10  inch,  plain  finish $ 50  I 902.— 15  inch,  plain  finish $1  00 

901. — 10  “ polished 60  I 903.— 15  u polished 1 25 

45°  x 45°  x 90°. 

905. — 7 inch,  plain  finish $ 50  | 907.— 12  inch,  plain  finish $1  00 

906. — 7 “ polished 60  I 908.— 12  “ polished 1 25 


Hardivood  Triangles , framed  ivith  open  centre . 

30°  x 60°  x 90°. 

910. — 6 inch $ 25  I 913.— 12  inch $ 40 

911. — 8 “ 30  I 914.— 14  “ 50 

912. — 10  ‘ 35  I 


45°  X 45°  x 90°. 


915. -5  inch 

916. — 7 “ 

917. — 9 “ 


$ 25  918.— 11  inch 
30  919.-13  “ 
40  | 


$ 50 
65 


8 8? 


260 


W.  & L.  E.  GURLEY,  TROY,  X.  Y. 


Hardwood  Triangles,  plain. 

30°  x 60°  x 90°. 

No.  Price 

920. — 5 to  inch $ 10  I 922.— 11  to  12  inch $ 20 

921. — 8 to  “ 15  1 

45°  X 45°  x 90°. 

925.-4  to  6 inch $ 15  | 926.-7  to  8 inch $ 20 


Batter  Slopes. 

928.— Set  of  three  forms  of  hard  rubber  for  Batters  of  walls  and  rock,  giving 
the  following  slopes : 1 in  4,  1 in  5, 1 in  6, 1 in  8,  1 in  10, 1 in  12,  per 


set . i $2  00 

Single  forms  of  set  No.  928,  containing  two  slopes,  each 75 


T SQUARES. 


930.  —15  inch 

931. -20  “ 

932. -25  u 


Hardwood  T Squares , fixed  head . 


$ 30 
40 
45 


933. — 30  inch 

934. -40  “ 

935. -50  “ 


$ 50 
85 
1 25 


Hardwood  T Squares , shifting  head . 

936. — 20  inch 

937. -25  “ 

938. -30  “ 


$1  00 
1 05 
, 1 10 


939.— 40  inch $1  50 


940.— 50 


1 75 


W.  & L.  E.  GURLEY,  TROY,  X.  Y. 

Rosetvood  T Squares,  fixed  head,  polished. 

No. 

941.-30  inch $1  75  I 942.-40  inch 

Rosetvood  T Squares , shifting  head,  polished. 

943.-30  inch $2  75  | 944.-40  inch $3  50 

Rubber  Blade  T Squares,  Hardwood  head,  fixed. 

$ 80  [ 948.— 30  inch $1  25 

1 00  I 949.  35  “ 1 TO 


946. — 20  inch 

947. -25  “ 


261 


Price 
$2  50 


Rubber  Blade  T Squares,  Hardwood  head,  shifting. 

951. -20  inch $1  75  I 953.-30  inch $2  50 

952. -25  “ 2 00  I 954.-35  “ . . 2 75 


T Squares , Steel  Blades  Nickel  Plated , Japanned  Iron 
heads , fixed . 

955.— 18  inch $3  25  I 957.— 30  inch $5 

956  _24  « 4 50  1 958.-36  “ 6 


T Squares , Steel  Blades  Nickel  Plated Japanned  Iron 
heads , shifting . 

959. — 18  inch $4  75  I 961.— 30  inch ...  $7  00 

960. — 24  “ 6 00  I 962.-36  “ 8 00 

Any  of  our  T Squares  with  longer  blades  made  to  order. 


OVALS,  HYPERBOLAS,  AND  PARABOLAS. 


965. — Pearwood  Ovals,  2 to  6 inches  long,  10  in  a set,  per  set $2  00 

966. —  Do.  \\  to  4^  do.  6 do.  do 1 50 

967. —  Do.  % to  7 do.  43  do.  do 5 00 

968. — Pearwood  Hyperbolas,  2 to  5 inches  long,  8 in  a set  1 40 

969. —  Do.  Parabolas,  12  do 3 00 

970. —  Do.  do.  to  6 inches  long,  8 do 1 40 


g s 


262 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


IRREGULAR  CURVES. 


WOOD. 


No.  Price 

980.— Whitewood  Irregular  Curves,  5 to  15  incjies  long,  various  patterns, 

each $ 20 


983.— Whitewood  Irregular  Curves,  of  superior  quality,  Nos.  23  to  25. 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


263 


RAILROAD  CURVES  OF  CARDBOARD,  WOOD,  AND 
RUBBER. 


985. 


The  following  curves  are  cut  to  a scale  of  inches,  the  outside  of  arcs 
only  finished. 

985.— Set  of  ten  Curves,  from  12  to  120  inches  radius,  varying  every  12  inches  : 

A. — Set,  complete,  of  card-board,  in  box $3 

B. —  Do.  wood,  do 4 

C. —  Do.  rubber,  do 8 

G86.— Set  of  seventeen  Curves,  from  12  to  60  inches  radius,  varying  every  3 
inches : 

A. — Set,  complete,  of  card -beard,  in  box $5  00 

B.  — Do.  wood,  do 7 50 

C. —  Do.  rubber,  do ; 14  00 

987.— Set  of  twenty-four  Curves,  from  ll/2  to  24  inches  radius. 

Varying  y2  inch  from  iy2  inches  to  10  inches, 

Do.  2 inches  do.  10  inches  to  24  inches : 


A. — Set,  complete,  of  card-board,  in  box  $7  50 

B. —  Do.  wood,  do 10  00 

C. —  Do.  rubber,  do 17  00 


The  following  Curves  are  cut  to  a scale  of  50  feet  to  the  inch,  and  have 
both  inside  and  outside  of  arcs  finished  : 

990.— Set  of  fifteen  Curves,  rising  every  30"  to  3°,  then  single  degrees  to  12° : 


A. — Set,  complete,  of  wood,  in  box $7  50 

B. —  Do.  rubber,  do 12  00 

9S1. — Set  of  twenty  Curves,  rising  every  30"  to  10° : 

A. — Set,  complete,  of  wood,  in  box $12  00 

B. —  Do.  rubber,  do 10  00 


The  following  Curves  are  cut  to  a scale  of  4f  0 feet  to  the  inch,  and  are 
finished  only  on  outside  of  arc : 

995.— Set  of  twenty  Curves,  from  30"  to  10°  by  every  30": 


A. — Set,  complete,  of  wood,  in  case ,$9  00 

B. —  Do.  rubber,  do 13  00 


S 8 § 


264 


W.  & L.  E.  GURLEY,  TROY,  X.  Y. 


HARD  RUBBER  IRREGULAR  CURVES. 


1000. 


W.  & L.  E.  GURLEY,  TROY,  X.  Y. 


265 


No. 

1000.— Hard  Rubber  Irregular  Curves  : 


!• — 5*4  inches 

long,  each $ 

35 

2.-514 

do.  

35 

3.-9 

do.  — 

50 

4.-9 

do. 

50 

5.-6 

do.  — 

40 

13.— 9 

do. 

50 

14.— 714 

do.  — 

35 

15.-814 

do.  — 

45 

16.-4% 

do.  — 

35 

17.— 9 

do.  — 

35 

18.-8 

do.  

40 

Price 


19. —  8 inches  long,  each $ 

20. — 1014  do,  

21.  — 7*4  do.  

22.  — 5 do.  

23. —  6 do.  

24. -  9 do.  

25. —  7 do.  

26. -  514  do.  

27. — 12  do.  

28. — 12  do.  2 


1030. — Hard  Rubber  Ellipses,  6 in  a set,  114  to  4%  in.  long,  per  set $1 

1031. —  Do.  10  do.  2 to  6 in.  do 2 


PARALLEL  RULES. 


1035. 


1042. 


Parallel  Rulers , Ebony , Brass  Mounted . 

1035. —  6 inch $ 25  j 1038.— 15  inch .$1  00 

1036. -  9 “ 50  | 1039. — 18  “ 125 

1037. -12  “ 75  | 1040.-24  “ 2 00 

1041.— Parallel  Ruler,  Ebony,  German-silver  Mounted,  12  inch $1  25 


Parallel  Rulers , Ebony , on  Rollers. 

1042. — 12  inch 

1043. — 15  “ 


$3  25  I 1044.— 18  inch $5  00 

4 00  I 


Parallel  Rulers , Ebony , on  Rollers , Ivory  Graduated 
Edges. 


1045. — 12  inch 

1046. — 15  “ 


$5  00  1 1047.-18  inch, 
6 50  I 


$7  50 


OCT 

OO  CTCTCTOOOCTCTOO 


266 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


Parallel  Eulers , all  Brass , on  Rollers . 

No.  Price 

1048. —  9 inch $6  50  I 1050.— 15  inch $10 

1049. -12  “ 8 00  I 1051.— 18  “ 12 


Numbers  1048  to  1051  furnished  Nickel-plated  at  an  extra  cost  of 
50c.  to  $1.00. 

Parallel  Rulers , all  German  Silver , on  Rollers . 

1052. — 12  inch $10  00  I 1054.— 18  inch $15  00 

1053. — 15  “ 12  00  I 


SECTION  LINERS. 

4060. — Bergner’s  Patent  Section  Liner,  in  Morocco  case $7  50 

1061. — Harden’s  Improved  Section  Liner 3 75 

1062. — Marion’s  Section  Liner,  German-silver  slide  and  screws,  with  either 

polished  satinwood,  or  rubber  triangle,  and  ruler 2 00 


1062. 


PANTOGRAPHS. 

$3  00 
5 50 


1063. -  Pantograph  of  hardwood  arms 

1064. —  Do.  pearwood,  arms  22  inches  long. 


8 8 


W.  & L.  E.  GURLEY,  TROY,  K.  Y. 


267 


THUMB  TACKS  AND  HORN  CENTRES. 


1065.  1068. 


1071.  1075.  1076. 


No  Price 

1065. — Thumb  Tacks,  brass,  round  flat  heads,  X inch  diameter,  per  doz $ 25 

1066. —  Do.  do.  do.  y2  do.  do 35 

1067. —  Do.  German-silver  do.  % do.  do 60 

1068. —  Do.  do.  do.  % do.  do 75 

1069. —  Do.  do.  do.  % do.  do.  1 00 

1071. — Do.  brass,  right-angled,  per  doz  75 

1075. — Horn  Centre 15 

1076. —  Do.  with  German-silver  rim 35 

1078.— Thumb-tack  Extractor  and  Impressor,  nickel  plated  25 


POCKET  RULES. 


* 1080.— One  Foot,  four  Fold,  boxwood,  each $ 25 

1081. —  Do.  do.  do.  edge  plates 50 

1082. —  Do.  do.  do.  brass  edges,  bound 75 

1085. — Two  Feet,  four  Fold,  boxwood 30 

1086. —  Do.  do.  do.  edge  plates 60 

1087. —  Do  do.  do.  brass  bound,  with  drafting  scales 1 00 

1089. — Two  Feet,  six  Fold,  boxwood,  graduated  8ths,  lOths,  ICOths,  and  16ths.  1 25 

1090. — One  Foot,  four  Fold,  ivory,  German-silver  mounted 1 25 

1091. — One  Foot,  four  Fold,  ivory,  German-silver  mounted,  graduated  in  8ths, 

lOths,  12ths,  16ths,  and  lOOths  of  a foot  on  edges 1 50 

1092. — One  Foot,  four  Fold,  ivory,  graduated  in  8ths,  lOths,  12lhs,  lOths,  and 

lOOths,  with  German-silver  edges,  bound 1 75 

1093. — One  Foot,  four  Fold,  ivory,  Caliper,  graduated  in  8ths,  lOths  12ths,  and 

16ths 2 50 

1093A.— One  Foot,  four  Fold,  ivory,  Caliper,  graduated  in  8lhs,  lOths,  12ths, 

and  16ths,  with  German-silver  edges,  bound 3 00 

1094. — Two  Foot,  four  Fold,  ivory,  German-silver  mounted,  with  8ths,  lOths, 

and  16ths  inches,  and  34,  34,  and  1 inch  drafting  scales 4 50 

1095. — Two  Feet,  four  Fold,  ivory,  same  as  No.  1094,  German-silver  bound. . . 5 50 


268 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


BOXWOOD  COMBINATION  RULE. 

1098.— Combination  Rule,  One  Foot,  Two  Fold,  boxwood. 

This  is  the  most  convenient  and  useful  pocket-rule 
ever  made  ; it  combines  in  itself  a Carpenter’s  Rule, 

Spirit  Level,  Square  Plumb,  Bevel,  Indicator  Brace, 

Scale,  Draughting  Scale  of  equal  parts,  T Square, 
Protractor,  Right-angle  Triangle,  and  with  a straight 
edge  can  be  used  as  a Parallel  Ruler,  all  the  parts  of 
which,  in  their  separate  application,  are  perfectly 
reliable $2  00 


12096. 


IMPROVED  TRAMMEL  POINTS. 


mo. 


W.  & L.  E.  GURLEY,  TROY,  X.  Y. 


269 


These  tools  are  used  by  all  who  have  occasion  to  strike  arcs  or  circles 
larger  than  can  be  done  by  compass  dividers.  They  may  be  used  on  a 
straight  wooden  bar  of  any  length,  and  when  secured  in  position  by 
the  thumb  screws,  all  circular  work  can  be  readily  laid  out.  They  are 
made  of  bronze,  and  have  steel  points,  either  of  which  can  be  removed 
and  replaced  by  pencil  socket,  which  accompanies  each  pair. 


No.  Price 

1110. — Small,  per  pair $1  25 

1111.  — Medium,  per  pair 150 

1112. — Large,  per  pair 1 75 


Horse  Shoe  Magnets. 


1115.— 2 inch .v $ 15 

1117. — 3 “ 25 

1118. -4  “ 45 


1119. -5  inch $ 70 

1120. -0  41  1 00 

1121.-7  “ 125 


1140. — Mahogany  Case,  stop  to  needle,  inches  square $1  50 

1141.  — Do.  do.  2 do.  2 00 

1142. —  Do.  do.  2J4  do 2 25 

1143. —  Do.  do.  3 do 2 75 

1144. — Brass,  round,  watch  pattern,  stop,  agate  centre,  1)4  inch 1 25 

1145. —  Do.  do.  do.  do.  2 do 1 50 

1146. — Brass,  round,  with  cover,  iy2  inches  diameter,  stop  to  needle 1 25 


1147. —  Do.  do.  do.  and  agate 

centre  to  needle 175 

1148. — Brass,  round,  watch  pattern,  stop,  agate  centre,  1)4  inch,  with  hinged 

cover 1 75 


270 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


No.  Price 

1149. — German-silver,  round,  watch  pattern,  stop,  agate  centre,  1 y2  inch,  with 

hinged  cover $2  50 

1150. — Pocket  Compass,  warch  pattern,  gilt,  enamelled  or  metal  face,  stem 

stop,  Bar  needle,  l)i  inches  in  diameter.  . 5 00 

1151. —  Do.  but  1J4  inches  in  diameter G 00 

1152.  — Do.  nickel -plated  or  gilt  case,  with  hiuged  cover,  spring  catch 

and  stop  to  needle  in  joint  of  cover 3 75 

1153.  — Bar  needle,  nickel-plated  or  gilt  case,  with  hinged  cover,  spring  catch 

and  stop  to  needle  in  joint  of  cover,  2 inches  in  diameter 5 00 

1154.  — Pocket  Compass,  watch  pattern,  gilt,  stem  stop,  in  case,  inches 

diameter,  Singer’s  patent  pearl  dial 5 50 

1155. — Pocket  Compass,  watch  pattern,  gilt,  stem  stop,  in  case,  1)4  inches 

diameter,  Singer’s  patent  pearl  dial 0 00 

1156.  — Pocket  Compass,  watch  pattern,  nickel-plated  hunting  case,  bar  needle, 

1)4  inches  in  diameter,  raised  ring,  metal  face 4 00 

1157. — Pocket  Compass,  watch  pattern,  nickel-plated,  but  1 % inches  in 

diameter 4 50 

1158. — Pocket  Compass,  nickel-plated  hunting  case,  raised  ring,  stop  to  needle, 

folding  sights,  2%  inches  in  diameter 7 00 

1159.  — Pocket  Compass,  nickel-plated  hunting  case,  raised  ring,  stop  to  needle, 

folding  sights,  with  levels 8 00 

1159A.— Geological  Compass,  of  Brass,  with  pendulum  for  ascertaining  the 

angle  of  dip  in  rocks  — 4 50 

1160. — Gilt  Charm  Compasses  to  hang  to  watch  guard 25  cts.  to  1 50 

1161. — Prismatic  Azimuth  Compass,  brass,  2%  in.  diam 18  00 

1162. —  Do.  do.  do.  do.  4 do 22  00 


1163. 

1163.— Pocket  Alt- Azimuth,  with  Telescope,  for  travelers  and  military  sur- 
veyors. Altitudes,  azimuths,  compass  bearings,  clinometer  degrees 
and  levels  are  all  obtained  by  this  instrument.  Size  6^4  * %V%  x Us,  in 
case $50  00 


w.  & L.  E.  GURLEY,  TROY,  K.  Y. 


271 


1150.  1164. 


No.  Price 

1164. — Pocket  Sextant,  with  Telescope,  very  accurate 42  50 

1165. — Surveyor’s  Cross — for  right  angles 3 00 

1166. — Pedometer,  for  measuring  distances  walked,  watch  form  and  size, 

nickel-plated  case  5 00 


POCKET  SPIRIT  LEVELS. 


1180. 


Pocket  Levels , Mounted  in  Brass. 


1180. -3  inch $ 75  I 1182.-  9 inch. 

1181. — 6 “ 1 50  I 1183.— 12  “ . . 

1185.— Level  Vials,  unmounted,  2 to  4 inches 

1186—  “ “ 4 to  6 “ 

1187. — “ “ ground  vials,  2 to  6 inches. 


$2  25 

3 00 

25 

35 

50c.  to  2 50 


272 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


MICROSCOPES,  Ac- 


simple  MICROSCOPES,  TO  FOLD  IN  CASES. 


1200.  1220.  1225.  1230.  1235.  1238. 


Hard  Rubber  Case  and  Frame , round  form , 1 double  convex 


No. 


lens . 


Price 


1200.  — % inch 

1201. — 1 “ . 
1202.— U4  “ . 


$ 40 
50 
75 


1203.— 1 14  inch, 
1205.— 2 “ 


$1  00 
1 50 


Hard  Rubber  Case  and  Frame , round  form , 2 double  convex 

lenses . 

1210. —%  and  % inch $ 75  1214.— 1%  andl%  inch $1  50 

1211.  — % “ 1 “ 1 00  1216. — 1%  “ 2 “ 2 50 

1213.— 1%  “ 1%  “ 1 25 


Hard  Rubber  Case  and  Frame , bellows  form,  1 double  con- 
vex lens . 

1220. — % inch $ 50  | 1222.— 1 inch $ 75 


Hard  Rubber  Case  and  Frame , bellows  form,  2 double  con- 
vex lenses . 

1225.—%  and  % inch $ 90  | 1227.—%  and  1 inch $1  25 


Hard  Rubber  Case  and  Frame,  belloivs  form,  S double  con 
vex  leyises. 


$1  65 


1230.—  % and  ';i  inch 


$1  25  | 1232.—%,  % and  1 inch 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


273 


No.  Price 

1235.  — Microscope  on  three  legs  with  screw  adjustment  for  focus $ 75 

1236.  — Linen  provers  or  microscope  for  counting  threads  in  linen  or  wool 

fabrics.  Hard  rubber  1 inch  open  space 175 

1237. —  Do.  Brass,  14  and  y2  in.  open  space 50 


1238.—  Do.  do.  ^ in.  square  can  be  changed  to  Txo8o  in  Diameter 60 


1240.  1245. 


1240.— Coddington  Lens,  brass  frame,  three  sizes. .$1  00,  $1  50  and  $2  00 

1244. —  Do.  silver  frame 2 25 

1245.  — Do.  do.  with  cover 2 50 

1246. —  Do.  do.  do.  large  size 4 00 


READING  AND  PICTURE  LENSES. 


Reading  Glasses , hard  rubber  frame,  double  convex  lens . 

1250, -2  inch $1  00  I 1252.— 3 inch $1  75 

1251. — 2H  “ 1 25  I 1254.-4  “ 3 00 

Reading  Glasses , hard  rubber  frame , double  convex  lens . 

1255. — 2 inch $1  25  I 1257.— 3 inch $2  00 

1256. -2^“  1 50 1 1259.-4  “ 3 00 

Reading  Glass , oxidized  metal  frame,  two  plano-convex  lenses . 

1260.-2^  inch $1  50  I 1262.-3^  inch $3  25 

1261— 3 “ 2 25  I 1263.— 4 “ 4 00 

1265 —Picture  Glass,  metal  frame  and  handle,  double  convex  lens,  5 inches 

diameter 5 qq 

1266.—  Do.  514  inches  diameter 6 00 


274 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


MARINE  AND  FIELD  GLASSES. 


The  power  and  sharpness  of  definition  of  a Field  Glass  depends  upon 
the  diameter  of  the  object-glass  ; the  greater  the  diameter  the  higher 
the  power,  and  more  clearly  distant  objects  are  seen. 

These  Glasses  are  designated  and  priced  according  to  the  diameter  of 
the  object  glasses  in  French  lines,  eleven  lines  being  equal  to  one 
inch. 


1300. 

No.  Price 

1300. — Six  Lens  Achromatic  Field  Glass,  metal  body,  covered  with  morocco, 

sun  shades  to  extend  over  the  object-glasses,  and  leather  case  with 
strap. 

A. — Body  4%  inches  long ; object-glasses  21  lines  in  diameter $?  50 

B. —  Do.  5%  do.  do.  24  do.  8 50 

C. —  Do.  6}4  do.  do.  26  do.  9 50 

1301. — U.  S.  Army  Signal  Service  Six  Lens  Achromatic  Marine  or  Field  Glass, 

metal  body,  covered  with  Turkey  morocco,  sun  shade  to  extend  over 
the  object-glass,  and  heavy  leather  case,  with  strap. 

A. — Body  5%  inches  long;  object-glasses  21  lines  in  diameter $13  00 

B. —  Do.  5%  do.  do.  24  do.  14  50 

C. —  Do.  GK  do.  do.  26  do.  15  50 

1302. — Bardou’s  U.  S.  Army  Signal  Service  Marine  or  Field  Glass,  six  lenses, 

acliromatie  object-glasses,  metal  body,  covered  with  Turkey  morocco 
sun-shade  to  extend  over  the  object-glasses,  and  heavy  leather  case, 
with  strap  ; very  superior. 

A —Body  6 inches  long  when  adjusted,  object-glasses  21  lines  in  diam.  16 

B. —  Do  6%  do.  do.  do.  24  do.  18 

C. —  Do.  1)4  do.  do.  do.  26  do.  20  50 


s s 


W.  & L.  E.  GURLEY,  TROY,  N\  Y. 


275 


No.  Price 

Bardou’s  U.  S.  Army  Signal  Service  Marine  or  Field  Glass,  six  lenses, 
achromatic  object-glasses,  body  covered  with  Turkey  morocco,  with 
hinge  adjustment  for  ditferent  widths  of  eyes,  sun-shades  to  extend 
over  the  object-glasses,  in  fine  leather  case,  with  strap. 

A. — Body  6 inches  long  when  adjusted,  object-glasses  21  lines  in  diam.$18  50 

B. —  Do.  6%  do.  do.  do.  24  do.  20  50 

C.  — Do.  7l/2  do.  do.  do.  26  do.  22  50 

1305.  — R n ncheni ail’s  Glass.  Six  Lens  Achromatic  Field  Glass,  metal 

body  covered  with  morocco,  sun-shades  to  extend  over  the  object- 
glasses,  in  fine  leather  case,  with  strap.  A superior  glass. 

A.— -Body  6%  inches  long,  object-glasses  26  lines  in  diameter 18  00 

1306.  —The  Gem.  A compact  Field  Glass,  which  is  equally  well  adapted  to 

the  theatre  or  field  ; and  for  the  latter  purpose,  as  well  as  -for  the  use 
of  the  race-course,  is  a powerful,  compact,  and  perfect  instrument, 
being  small  enough  to  be  carried  in  the  pocket,  with  good  power, 


large  field  of  view,  and  sharp  definition. 

A. — Body  Sl/2  inches  long,  object-glasses,  19  lines  diameter 20  00 

B. —  Do.  4 do.  do.  21  do.  21  00 


IMPROVED  OPERA  AND  FIELD  GLASS. 

This  glass  is  similar  to  “ The  Gem,”  but  has  a double  draw  to  the  eye- 
end,  like  a telescope  ; is  very  portable,  with  good  power. 


1307.— A.— Body  3 M inches  long,  object-glasses,  17  lines  diameter $16  00 

B.—  Do.  4 do.  do.  19  do 17  00 


1308.— Bardou’s  Pocket  Army  Field  Glass,  conical  body,  5 inches  long,  object- 
glasses  19  lines  diameter;  very  portable,  with  good  power  and 
definition 16  00 

Note.— We  also  have  constantly  on  hand  a full  and  choice  assortment 
of  plain  and  fancy  Opera  Glasses,  of  best  make.  Sizes  from  10  to  19 
lines  diameter.  Prices  from  $3,50  to  $25  00  each. 


276 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


ACHROMATIC  TELESCOPES. 


1325. — Telescope,  wood  body,  3 draws,  15  inches  drawn  out,  6 inches  shut, 

object-glass  1 inch  in  diameter,  power  13  times  $2  50 

1326.  — Telescope,  wood  body,  3 draws,  16  inches  drawn  out,  6 inches  shut, 

object-glass  inches  in  diameter,  power  16  times 3 50 

1327.  Telescope,  wood  body,  3 draws,  23  inches  drawn  out,  8 inches  shut, 

object-glass  1%  inches  in  diameter,  power  20  times. . . . . 4 75 

1328. — Telescope,  wood  body,  3 draws,  30  inches  drawn  out,  10  inches  shut, 

object-glass  1%  inches  in  diameter,  power  25  times 7 00 

1329. — Telescope,  wood  body,  4 draws,  37  inches  drawn  out,  11  inches  shut, 

object-glass  1%  inches  in  diameter ; superior  glass  ; power  35  times. . 12  00 

1330.  — Telescope,  wood  body,  4 draws,  42  inches  drawn  out,  1114  inches  shut, 

object-glass  2%  inches  in  diameter,  power  40  times 20  00 

1331. — Telescope,  wood  body,  4 draws,  48  inches  drawn  out,  13>£  inches  shut, 

object-glass  2%  inches  in  diameter,  power  50  times 30  00 


TOURISTS’  GLASSES. 


1341. 

1341.  — Tourist’s  Achromatic  Spy-glass,  with  brass  body,  covered  with  black 

Turkey  morocco ; three  draws,  17  inches  long  when  drawn  out,  6 
inches  long  when  shut  up  ; object-glass  inches  diameter;  sun-shade 
to  slip  beyond  the  object-glass ; heavy  leather  caps  to  cover  both  the 
eye-glass  and  object-glass  ; strong  leather  strap  to  sling  over  the 
shoulder.  Power  20  times 8 00 

1342. — Same  as  No.  1341,  but  is  21  inches  long  when  drawn  out,  7 inches  long 

when  shut  up  ; object-glass  1 % inches  diameter.  Power  25  times  ...  11  00 

1343.  — Same  as  No.  1341,  but  is  24  inches  long  when  drawn  out,  9 inches  long 

when  shut  up  ; object-glass  1%  inches  diameter.  Power  30  times 14  00 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


277 


No.  Price 

1344. — Signal  Service  Spy-glass,  same  as  No.  1341,  but  has  four  draws,  and  is 

36  inches  long  when  drawn  out,  10  inches  long  when  shut  up  ; object- 
glass  2 inches  diameter.  Power  35  times . $20  00 

1345. — Rifle  Spy-glass,  10%  inches  long,  body  covered  with  black  leather ; 

achromatic  object-glass  X inch  in  diameter.  Power  1C  times 2 50 

1350. — Wooden  Tripod  Stand,  with  vertical  and  horizontal  motion,  upon  which 

to  place  a spy-glass  ; an  exceedingly  useful  article,  as  a glass  of  much 
power  cannot  be  held  in  the  hand  with  sufficient  steadiness  to  pro- 
duce the  bast  effect 5 00 

1351. — Brass  Clamp  with  Gimlet  Screw,  to  fasten  a spy-glass  to  a post  or  tree, 

three  sizes  to  fit  any  of  the  foregoing  spy -glasses $1  50  to  3 00 


ASTRONOMICAL  TELESCOPES. 


1355.  — Astronomical  Telescope.  Polished  wood  body,  47  inches  long,  mounted 

on  firm  tripod  stand,  achromatic  object-glass  3 inches  in  diameter, 
one  terrestrial  eye-piece,  rack  and  pinion  for  adjusting  the  focus. 
Power  50  times  $65  00 

1356. — Astronomical  Telescope.  Same  as  No.  1355,  with  one  terrestrial  eye- 

piece giving  power  of  50  times,  and  one  celestial  eye-piece  giving 
power  of  100  times 70  00 

1357. — Astronomical  Telescope.  Body  of  Brass,  35  inches  long,  has  rack 

and  pinion  for  focusing,  achromatic  object-glass  2J4  inches  in  diame- 
ter, terrestrial  eye-piece,  power  40  times;  celestial  eye-piece,  with 
black  sun-glass,  power  80  times  ; firm  tripod  stand  of  walnut,  having 
horizontal  and  vertical  movements,  walnut  case,  with  lock  and  key, 
for  receiving  the  body  and  eye-pieces 70  00 

1358. — Astronomical  Telescope.  Same  as  No.  1357,  but  with  body  40  inches 

long,  achromatic  object-glass  3 inches  in  diameter,  terrestrial  eye- 
piece, power  50  times ; celestial  eye-piece,  with  black  sun-glass, 
power  100  times,  with  walnut  case 100  00 


278  W.  & L.  E.  GURLEY,  TROY,  N.  Y. 

DRAWING  PAPER. 

Samples  of  drawing  paper,  tracing  paper,  tracing  cloth,  profile  and 
cross-section  papers,  sent  with  prices  on  application. 

WHATMAN’S  HOT  AND  COLD  PRESSED  DRAWING 
PAPERS. 

SELECTED,  BEST  QUALITY. 

No.  Price 

1400. — Demy,  20  x 15,  per  quire,  $1  00  ; per  sheet $ 06 

1401. — Medium,  22x17,  do.  140;  do 08 

1402. — Royal,  24x19,  do.  1 75;  do 10 

1403. — Super  Royal,  27x19,  do.  2 20;  do 12 

1405.— Imperial,  30  x 21,  do.  3 00 : do 20 

1407. — Atlas,  33  x 26,  do.  4 75 ; do 25 

1408. — Double  Elephant,  40  x 26,  do.  5 50  ; do 30 

140 A — Antiquarian,  52  x 31,  do.  27  50 ; do 1 50 

BLEACHED  MANILLA,  BUFF  TINT. 

FOR  WORKING  DRAWINGS,  BEST  AMERICAN  MAKE,  IN  ROLLS 
OF  ABOUT  50  POUNDS. 

1415. — 36  inches  wide,  thick,  per  pound,  15  cts. ; per  yard. $ 10 

1416. -40  do.  do.  do.  do 12 

1418. — 48  do.  do.  do.  do 15 

1419. — 54  do.  do.  do.  do 18 

AMERICAN  WHITE  ROLL  DRAWING  PAPER. 

VERY  STRONG  AND  OF  EXCELLENT  QUALITY,  IN  ROLLS  OF 
40  TO  50  POUNDS. 

1420. — 36  inches  wide,  per  pound,  60  cts. ; per  yard — $ 25 

1421.  — 42  do.  do.  do.  do 30 

1422.  — 46  do.  do.  do.  do ....  35 

EXCELSIOR  WHITE  ROLL  DRAWING  PAPER. 

IN  ROLLS  OF  30  TO  50  POUNDS. 

1425. — 36  inches  wide,  medium,  per  pound,  45  cts. ; per  yard $ 25 

1426. — 42  do.  do.  do.  do.  do 30 

1427. -56  do,  do,  do.  do.  do,  50 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


2?9 


BEST  EGGSHELL  DRAWING  PAPER. 

IN  ROLLS  OF  30  TO  40  POUNDS. 

No.  Price 

1430. — 4*2  in.  wide,  medium,  rough  surface,  per  pound,  45  cts.;  per  yard $ 35 

1431. — 58  in.  wide,  medium,  rough  surface,  per  pound.  45  cts.;  per  yard 45 

1432. — 58  in.  wide,  heavy,  rough  surface,  per  pound,  45  cts.;  per  yard 50 

The  pound  price  applies  only  to  full,  unbroken  rolls. 

MOUNTED  DRAWING  PAPER. 

WHITE,  MOUNTED  ON  MUSLIN,  IN  ROLLS  OF  10  YARDS. 

1438. — American,  36  inches  wide,  smooth  surface,  per  roll,  $8.00  ; per  yard $ 90 

1439. —  Do.  42  do.  do.  do.  9.00 ; do 1 00 

1441. — Excelsior,  42  do.  do.  do.  9.00 ; do 1 10 

1442. —  Do.  56  do.  do.  do.  13.00 ; do 1 51 

1145.— Eggshell,  42  do.  rough  surface,  do.  9.00 ; do 1 10 

1446. —  Do.  54  do.  do.  do.  12.00 : do 1 25 

1447.  — Do.  58  do.  do.  do.  13.50;  do 1 50 

Large  pieces  for  City,  County,  or  State  Maps.  Mounted  to  order. 

TRACING  PAPER. 

1450. — English,  in  rolls  of  20  yards,  40  inches  wide,  per  roll $4  00 

1451. — French,  common,  in  rolls  of  11  yards,  43  inches  wide,  per  roll 1 50 

1452.  — Do.  do.  do.  22  do.  43  do.  do 2 

1453. —  Do.  vegetable,  do.  22  do.  54  do.  do 4 

1454. — Parchment,  very  tough  and  transparent,  and  does  not  discolor  from 

age,  in  rolls  of  33  yards,  38  inches  wide,  per  roll 8 00 

1455. — German,  tough  and  transparent,  in  rolls,  43  inches  wide,  22  yards  long, 

per  roll 5 00 

1456. — Vegetable  Royal,  25  x 19  inches,  per  quire  $2  20  ; per  sheet 12 

1457. —  Do.  Super  Royal,  26x21  inches,  per  quire,  $3  00  ; per  sheet 20 

1458. —  Do.  Double  Elephant,  40x28  inches,  per  quire,  $8  00  ; per  sheet.  50 

1459.  — “ Flaxine,”  American  tracing  paper,  white,  very  strong. 

A. — 31  x 21  inches,  per  quire,  $2  50  ; per  sheet 12 

B. — 40  x 30  do.  3 50  ; do 17 

1460. — Bond  paper,  for  tracings,  very  tough. 

A. — 21  x 16  inches,  per  quire,  $1  00  ; per  sheet 05 

B. — 24  x 19  do.  1 20 ; do 06 

C. — 30x19  do.  140;  do 07 


§ 3? 


280 


W.  & L.  E.  GTJELEY,  TROY,  N.  Y. 


TRACING  OR  VELLUM  CLOTH. 

IN  ROLLS  OF  24  YARDS,  FACE  GLAZED  AND  BACK  DULL, 

SUITABLE  FOR  PENCIL  MARKS. 

•N°’  Price 


1465.— Imperial,  18  inches  wide,  per  roll,  $4  00  ; per  yard . . $ 25 

1466—  Do.  30  do.  do.  6 90 ; do 40 

1467. —  Do.  36  do.  do.  7 50;  do * 45 

1468.  — Do.  42  do.  do.  10  50 ; do „ , 60 


THE  BLUE  PROCESS  OF  COPYING  TRACINGS. 


Special  attention  has  recently  been  directed  to  this  easy  process  of  copying 
tracings,  and  its  great  value  to  all  Engineers,  Architects,  and  Mechanical  Draughts- 
men fully  recognized. 

The  instructions  in  using  are— 

1.  Provide  a flat  board  as  large  as  the  tracing  which  is  to  be  copied. 

2.  Lay  on  this  board  two  or  three  thicknesses  of  common  blanket  or  its  equiva- 
lent, to  give  a slightly  yielding  backing  for  the  paper. 

3.  Lay  on  the  blanket  the  prepared  paper  with  the  sensitive  side  uppermost. 

4.  Lay  on  this  paper  the  tracing,  smoothing  it  out  as  perfectly  as  possible  so  as 
to  insure  a perfect  contact  with  the  paper. 

5.  Lay  on  the  tracing  a plate  of  clear  glass,  which  should  be  heavy  enough  to 
press  the  tracing  close  down  upon  the  paper.  Ordinary'plate-glass  of  three-eighths 
thickness  is  quite  sufficient. 

6.  Expose  the  whole  to  a clear  sunlight  by  pushing  it  out  on  a shelf  from  a win- 
dow, or  in  any  other  convenient  way,  from  four  to  six  minutes  [in  winter,  six  to 
ten  minutes].  If  a clear  sky  only  can  be  had,  the  exposure  must  be  continued  from 
twenty  to  thirty  minutes ; and  under  a cloudy  sky  from  sixty  to  ninety  minutes 
may  be  needed,  the  shade  depending  on  the  time. 

7.  Kemove  the  prepared  paper  and  wash  it  freely  for  one  or  two  minutes  in  clear 
water,  and  hang  it  by  one  corner  to  dry. 


PREPARED  SENSITIVE  PAPERS. 

Packed  in  tubes  to  keep  from  light,  one  dozen  sheets  in  each  tube,  and 
are  always  ready  for  immediate  use. 

1410.— Demy,  21  x 16,  per  dozen $ 85 

1473.  — Super  Eoyal,  28  x 20,  do 1 65 

1474. — Double  Medium,  36  x 23,  do 2 25 

1476.— Double  Elephant,  40  x 27,  do 3 50 

1478. — Sensitized  Solar  Printing  Paper,  42  inches  wide,  in  continuous  rolls  of 

10,  20,  or  50  yards,  per  yard 40 

1479. — Photo-Solution,  per  bottle 4 40 


w.  & L.  E.  GURLEY,  TROY,  1ST.  Y. 


281 


ROLL  DRAWING  PAPER  FOR  SENSITIZING. 


No.  Price 

1480.  — 42  inches  wide,  per  roll  of  10  yards,  $2  50 ; 55  yards $8  50 

1481. — 60  do.  do.  do.  3 50;  do 12  00 

1482. — Steinbach’s,  53  inches  wide,  very  superior,  light,  per  yard 35 

1483—  Do.  do.  do.  heavy,  do 50 

1484.—  Do.  2614  do.  do.  do.  do 30 


SOLID  SKETCHING  BLOCKS. 

Each  Block  consists  of  32  leaves  of  best  quality  Whatman’s  Drawing 
Paper. 


I486.— 4to  Royal,  12x9,  unbound,  $1  50  ; bound* $2  75 

1488. — 8vo  Imperial,  10  x 7,  do.  125;  do 2 25 

1489.  — 4to  do.  14  x 10,  do.  2 25  ; do 3 50 

1490.  — Half  do.  20  x 14,  do.  4 00  ; do 5 75 


* The  binding  has  Cloth  Sides  and  Leather  Back,  with  a Portfolio  and  Loop  for 
Pencil  inside.  The  Portfolio  will  last  for  a number  of  blocks. 


SKETCHING  OR  DESIGNING  PADS. 


1492. — Sketching  Pads,  plain  block,  7x5  inches,  25  leaves,  rulings  either  4,  8, 

10,  or  12  spaces  to  inch,  each $1  25 

1493. — Sketching  Pads,  plain  block,  14  x 10  inches,  25  leaves,  rulings  either  4, 

8, 10,  or  12  spaces  to  inch,  each 2 50 


TOWNSHIP  PLOTTING  PAPER. 


1495. — Township  Plotting  Paper,  Rulings  6x6  blocks,  blocks  1 inch  square, 

per  100  sheets. $2  00 

1496. — Township  Plotting  Paper,  Rulings  12  x 12  blocks,  blocks  2 inches  square, 

per  100  sheets 2 50 


282 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


PROFILE  PAPERS. 


Printed  in  red  or  green. 


Profile  Paper,  Plate  B. 


Profile  Paper,  Plate  C. 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


283 


Profile  Paper,  Metric. 


PROFILE  PAPER. 

N°-  Price 

1500.— Plate  A,  42 x 15  in.,  horizontal  ruling,  4,  vertical,  20  to  m.,  per  sheet. , . $ 40 
1501— Plate  B,  42  x 13%  do.  4,  do.  30  do.  do.  ...  40 

1502. — Plate  C,  42 x 15  do.  5,  do.  25  do.  do.  ...  40 

Nos.  1500, 1501,  and  1502,  per  quire 8 50 

1503. — Continuous  Profile  Paper  Plales,  A or  B,  rulings  20  inches  wide,  per 

Fard 30 

1505— Metric.— In  Continuous  Roll,  rulings  50  centimetres  wide,  in  milli- 
metres, with  each  fifth  millimetre,  each  centimetre,  and  each  deci- 
metre, proportionally  heavier  than  the  millimetres.  Price,  per  yard. . 30 


MUSLIN  BACKED  ROLL  PROFILE  PAPER, 


1510— Muslin  Backed  Roll  Profile  Paper,  of  either  Plate  A or  B,  rulings  20 

inches  wide,  in  rolls  of  20  yards,  per  yard $ 75 

1515.— Metric.— Muslin  Backed,  Rulings  20  inches  wide,  in  rolls  of  20  yards, 

per  yard 75 


CROSS  SECTION  PAPERS. 


Printed  in  red  or  green. 

1520— Topographical  Paper,  17x14  inches,  ruled  400  feet  to  the  inch,  per 

quire,  $1.75,  per  sheet  

1521.  Trautwine’s  Cross  Section  and  Diagram,  10  feet  to  inch,  for  embank- 
ments of  14  and  24  feet,  roadway,  and  for  excavations  of  18  and  28 
feet,  rulings  19%  x 12  inches,  per  quire,  $5.00,  per  sheet 


25 


284  W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


Plate  C. 

No.  Price 

1522.— Cross  Section  Paper,  Plate  C,  rulings  20  x 16  inches,  8 feet  to  inch,  per 

quire,  $5.00,  per  sheet $ 25 


Plate  F.  • 

1523.— Cross  Section  Paper,  Plate  F,  rulings  20x16  inches,  10  feet  to  inch, 

per  quire,  $5.00,  per  sheet $ 25 


Plate  G. 

1524.— Cross  Section  Paper,  Plate  G,  rulings  22x16  inches,  10  feet  to  inch, 

every  fifth  line  heavy,  per  quire,  $5.00,  per  sheet $ 25 


W.  & L.  E.  GURLEY,  TROY.  K.  Y. 


285 


Plate  H. 

No.  Price 

1525. — Cross  Section  Paper,  Plate  H,  rulings  21  x 16  inches,  16  feet  to  inch,  per 

quire,  $5.00,  per  sheet $ 25 


Metric. 


1526.— Cross  Section  Paper,  Metric,  rulings  every  two  millimeters,  size  of 


sheet,  50  x 40  centimeters,  per  quire,  $5.00,  per  sheet $ 25 

1527. — Cross  Section,  Plate  G,  printed  on  Parchment  Tracing  Paper,  in  sheets, 

20  x 18  inches,  per  quire,  $5.00,  per  sheet . . 25 


The  following  list  of  Cross  Section  Papers,  being  ruled,  are  much 
cheaper  than  those  printed  from  copper  plates,  and  are  sufficiently 
accurate  for  sketching  or  designing  purposes. 

1528.— Ruled  Cross  Section  Paper,  4 spaces  to  inch,  28  x 20  inches,  per  quire  . . 2 50 


1529.— 

Do. 

do. 

8 

do. 

to 

00 

to 

o 

do. 

do. 

2 50 

1530.- 

Do. 

do. 

10 

do. 

28x20 

do. 

do. 

2 50 

1531.— 

Do. 

do. 

10 

do. 

28x20 

do. 

5 to  block, 

per  quire 2 

1532.— Ruled  Cross  Section  Paper,  12  spaces  to  inch,  28  x 20  inches,  per  quire. . 2 


8 § 


286 


W.  & L.  E.  GURLEY,  TROY,  n.  y. 


BOUND  PROFILE  BOOKS. 


These  books  are  for  field  or  office  purposes,  being  printed  on  both  sides 
of  a tough  thick  paper,  and  bound  in  flexible  covers,  convenient  for 
the  pocket.  Each  page  will  contain  a profile  of  three  thousand  feet  in 
length,  so  that  each  folio  will  contain  an  average  section  of  a road  as 
usually  laid  out  for  construction.  Railroad  and  other  engineers  will 
find  them  very  useful.  Size  of  book  954  by  5%  inches.  The  rulings 
correspond  to  our  large  profile  plates  A and  B. 


No. 

1540.— Plate  A,  25  leaves,  imitation  Turkey  morocco,  with  elastic  band. . . 

Price 
. . . . $3  50 

1541. — Do. 

50 

do. 

do.  do. 

do.  

....  5 Op 

1542. — Do. 

100 

do. 

do.  do. 

do. 

. . . . 8 00 

1543.-  Do. 

50 

do. 

Turkey  morocco,  turned  edges, 

do.  

. . . . 6 00 

1544. — Do. 

100 

do. 

do.  do. 

do. 

...  9 00 

1545.— Plate  B,  25 

do. 

imitation  Turkey  morocco, 

do. 

. . . 3 50 

1546.—  Do. 

50 

do. 

do.  do. 

do. 

...  5 00 

1547.—  Do. 

100 

do. 

do.  do. 

do.  

. . . 8 00 

1548.—  Do. 

50 

do. 

Turkey  morocco,  turned  edges, 

do. 

. . . . 6 00 

1549.—  Do. 

100 

do. 

do.  do. 

do.  . . . 

...  9 00 

CONTINUOUS  PROFILE  BOOKS. 


These  are  an  improvement  over  the  books  described  above,  as  they 
admit  of  the  use  of  a continuous  sheet  for  profile  use.  They  are 
printed  upon  fine  sheets  of  paper,  and  mounted  upon  a continuous 
piece  of  muslin  and  bound  in  book  form. 

1550.— Plate  A,  8 x 554  inches,  profile  12  miles,  bound  in  morocco,  with  band. . $3  00 


1551.— 

Do. 

do. 

do. 

25 

do. 

do. 

do. 

..  5 00 

1552.— 

Do. 

do. 

do. 

50 

do. 

do. 

do. 

..  8 59 

1553.— 

Do. 

do. 

do. 

100 

do. 

do. 

do. 

. . 14  00 

1554.— Plate  B, 

8 x 4%  inches, 

do. 

12 

do. 

do. 

do. 

..  3 00 

1555.— 

Do. 

do. 

do. 

25 

do. 

do. 

do. 

..  5 00 

1556.— 

Do. 

do. 

do. 

50 

do. 

do. 

do. 

..  8 50 

1557.— 

Do. 

do. 

do. 

100 

do. 

do. 

do. 

. . 14  00 

Profile  Books,  either  plate,  bound  in  seal  skin,  with  turned  edges,  $1.50 
additional  to  the  above  prices.  Special  lengths  made  to  order  and 
bound  as  may  be  desired. 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


287 


ENGINEERS’  FIELD  BOOKS. 

No.  Price 

1560. — Level  Books,  7*4  inches,  per  dozen,  $5  00 ; each $ 50 

1561. — Transit  Books,  7x4  inches,  per  dozen,  $5  00 ; each  50 

1562. — Record  Books,  7x4  inches,  per  dozen,  $5  00 ; each 50 

1563  - Cross  Section  Books,  8x7  inches,  for  Topography,  per  dozen,  $10  00; 

each 1 00 

1564.— Profile  Level  Books,  7x4  inches,  per  dozen,  $7.50  ; each 75 


288  W.  & L.  E.  GURLEY,  TROY,  ,N.  Y. 

LYONS’  TABLES. 

No.  Price 

1570.— Lyons’  Tables  A set  of  Tables  for  finding  at  a glance  the  true  cubical 
contents  of  Excavation  and  Embankments  for  all  Bases,  and  for  every 
variety  of  Ground  aftd  Side  Slopes.  By  M.  E.  Lyons,  C.  E. 

Sheet  No.  1.  General  Table  for  all  Bases  and  all  Slopes. 

Do.  2.  For  Side  Hill  Cuts  and  Fills. 

Do.  3.  Base  12  feet  Slopes 114  to  1 

Do.  4.  do.  14  do 1>^  to  1 

Do.  5.  do.  15  do X to  1 

Do.  6.  do.  15  do 1 to  1 

Do.  7.  do.  15  do 1%  to  1 

Do.  8.  do.  16  do 34  to  1 

Do.  9.  do.  16  do 1 to  1 

*Do.  10.  do.  18  do 34  to  1 

*Do.  11.  do.  18  do.  % to  1 

*Do.  12.  do.  18  do 1 to  1 

*Do.  13.  do.  18  do.  1*4  to  1 

Do.  14.  do.  20  do.  1*4  to  1 

Do.  15.  do.  24  do.  *4  to  1 

Do.  16.  do.  24  do 1*4  to  1 

Do.  17.  do.  25  do 1%  to  1 

Do.  18.  do.  26  do.  I34  to  1 

Do.  19.  do.  28  do 14  to  1 

Do.  20.  do.  30  do 1 to  1 

Do.  21.  do.  30  do 114  to  1 

Do.  22.  do.  30  do 114  to  1 

Do.  23.  do.  32  do 1 to  1 

Do.  24.  do.  32  do 114  to  1 

The  Tables  are  printed  in  clear,  bold  type,  on  tinted  paper,  sheets  25  x 16 
inches.  They  may  be  used  by  candle-light  without  injuring  the  eye- 
sight. Each  sheet  is  complete  in  itself,  and  embraces  all  that  is 
wanted  in  connection  with  Base  or  Slope  designated,  whether  on  level 
or  side-hill  cross  section. 

Per  sheet,  25  cents ; bound  in  one  volume $8  50 

1571.— Zimmerman’s  Universal  Table,  for  Excavations  and  Embankments, 
adapted  to  any  base  and  slope  whatever,  and  the  calculations  of  all 
solids  to  which  the  Prismoidal  Formula  is  applicable.  By  Wm.  Zim- 
merman, C.  E.  Price 100 


* Out  of  print. 


W.  & L.  E.  GUliLEY,  TBOY,  N.  Y. 


289 


INK  SLABS,  AND  SAUCERS. 


1575.  1585. 


1580. 


Ink  Slabs. 

For  India  Ink  and  Colors  ; containing  3 holes  or  cups  and  1 slanting  division. 


No.  Price 

1575. — Measuring  224  x 1*4  inches,  each $ 15 

1576. —  Do.  324x2%  do 25 

1577. —  Do.  4%  x2%  do 35 

1578. —  Do.  4*4x3  do 40 

1579. —  Do.  5 x3*4  do 45 

1580. — Patent  Ink  Slab,  4*4  x \ % inches,  with  cover,  each. 50 

1581. —  Do.  5%x2%  do.  do,  60 

1582. — Slate  Ink  Slab,  4x4  inches,  with  ground  glass  cover,  each  75 


Cabinet  Nests . 

Porcelain  Saucers  in  nests ; fitted  on  each  other. 


1585.  — Containing  5 saucers  and  a cover,  2^4  inches  in  diameter,  per  nest $ 60 

1586. -  Do.  5 do.  2%  do.  do 70 

1587. —  Do.  5 do.  314  do.  do 

1588—  Do.  5 do.  3%  do.  do 1 

1589. — Architect’s  Basin,  with  8 divisions  and  cup 1 

1590. —  Sloping  Tile,  3 divisions  4 x 2*4  inches,  each 

1591. —  Do.  4 do.  734 x 3>4  do.  

1592. —  Do.  5 do.  7%x3%  do 45 

1593. —  Do.  6 do.  7%  x 3%  do 55 


290 


W.  & L.  E.  GURLEY,  TROY,  NT.  Y, 


WINSOR  & NEWTON'S  WATER  COLORS. 


HARD  COLORS  IN  CAKES,  OR  MOIST  IN  CHINA  PANS. 


Whole  Cake. 


Half  Cake. 


WINSORS:  N£  W TONS 
MOIST  COLOUR 

38  f)ci  ihbone  Place 
LONDON 

SERIA. 


Whole  Pan. 


VSOR  & NEWTONX 
Gist  colour* 
/flathbome  PlaceJfiT 
LONDON 
COBALT 


Half  Pan. 


No. 

1600.— Whole  25  cents  ; Half. 

1 Antwerp  Blue. 

2 Bistre. 

3 Blue  Black. 

4 British  Ink.* 

5 Bronze.* 

6 Brown  Ochre. 

7 Brown  Pink. 

8 Burnt  Sienna. 

9 Burnt  Umber 

10  Chinese  White. 

11  Chrome  Yellow. 

12  Cologne  Earth. 

13  Deep  Chrome. 

14  Dragon’s  Blood.* 

15  Emerald  Green. 


16  Flake  White.* 

17  Gamboge. 

18  Hooker’s  Green  No.  1. 

19  Hooker’s  Green  No.  2. 

20  Indian  Red. 

21  Indigo. 

22  Italian  Pink. 

23  Ivory  Black. 

24  King’s  Yellow.* 

25  Lamp  Black. 

26  Light  Red. 

27  Naples  Yellow. 

28  Neutral  Tint. 

29  New  Blue. 

30  Olive  Green. 


Price 

$ 15 

31  Orange  Chrome. 

32  Payne’s  Grey. 

33  Prussian  Blue. 

34  Prussian  Green. 

35  Raw  Sienna. 

36  Raw  Umber. 

37  Roman  Ochre. 

38  Sap  Green. 

39  Terre  Verte. 

40  Vandyke  Brown. 

41  Venetian  Red. 

42  Vermillion. 

43  Yellow  Lake. 

44  Yellow  Ochre. 


1601.— Whole  45  cents  each  ; Half. 


45  Black  Lead.* 

46  Brown  Madder. 

47  Cerulean  Blue. 

48  Constant  White.* 

49  Crimson  Lake. 


50  Indian  Yellow. 

51  Mars  Yellow. 

52  Neutral  Orange. 

53  Purple  Lake, 

54  Roman  Sepia. 


25 

55  Rubens’  Madder. 

56  Scarlet  Lake. 

57  Scarlet  Vermillion. 

58  Sepia. 

59  Warm  Sepia, 


W.  & L.  E.  GURLEY,  TROY,  N.  Y.  291 

No.  Price 

1602 —Whole,  65  cents  each ; Half $ 35 


60  Cobalt  Blue.  | 61  Orange  Vermillion.  | 62  Violet  Carmine. 


1603.— Whole,  90  cents  each ; Half 45 

63  Aureolin.  69  French  Blue  (or  74  Lemon  Yellow. 

64  Burnt  Carmine.  French  Ultramarine).  75  Pink  Madder. 

65  Cadmium  Yellow,  70  Gallstone.  76  Pure  Scarlet. 

Pale.  71  Green  Oxide  Chro-  77  Rose  Madder 

66  Cadmium  Yellow.  mium.  (or  Madder  Lake). 

67  Cadmium  Orange.  72  Indian  Purple.  78  Viridian. 

68  Carmine.  | 73  Intense  Blue. 


1604.— Whole,  $1.40  each  ; Half 70 

79  Field’s  Orange  Ver.*  I 81  Mars  Orange.  I 83  Smalt. 

80  Madder  Carmine.*  I 82  Purple  Madder.  ' 84  Utramarine  Ash. 


1605.— Quarter  Cake,  each 2 25 

85  Genuine  Ultramarine. 

Colors  not  made  in  pans  are  marked  *. 

The  following  colors  are  generally  used  by  Architects  and  Civil  and 
Mechanical  Engineers  : 

Burnt  Umber  to  represent  Earth. 


Do.  Sienna 

do. 

Wood. 

Light  Red 

do. 

Brick. 

Sepia  and  Yellow  Ochre 

do. 

Stone. 

Prussian  Blue 

do. 

Wrought  Iron. 

Payne's  Grey 

do. 

Cast  do. 

Gamboge 

do. 

Brass. 

Do.  and  Carmine 

do. 

Copper. 

Prussian  Blue  and  Carmine 

do. 

Steel. 

In  Topography  the  following  colors  are  generally  used. 
Hooker’s  Green  No.  2 to  represent  Grass. 


Burnt  Sienna  do. 

do.  and  Hooker’s  Green  do. 
Indigo  do.  do.  do. 

Gamboge  do.  do.  do. 

Yellow  Ochre  do. 

Indigo  do. 

Carmine  do. 

Sepia  do. 

do.  do. 


Cultivated  ground. 

Uncultivated  do. 

Swamp. 

Trees. 

Roads  and  Streets. 

Water. 

Buildings,  Bridges,  and  Masonry. 
Hills. 

Shade  lines  and  shadows. 


W.  & L.  E.  GURLEY,  TROY,  X.  Y. 


292 


WATER  COLOR  SLIDE-LID  BOXES. 


No.  Price 

1610. — Color  Boxes  to  hold  6 whole  or  half  cakes $ 40 

1611. —  Do.  12  do.  50 

1612. —  Do.  18  do.  60 

1613. —  Do.  24  do.  75 


EMPTY  JAPANNED  TIN  BOX. 

FOR  MOIST  COLORS. 


1615. 


1615. — For  6 full  or  12  half-pans,  each $1  00 

1616. — For  12  do.  24  do.  . . 1 45 

1617. — For  16  do.  32  do.  1 65 

1618— For  24  do.  48  do.  2 00 


WINSOR  & NEWTON’S  WATER  COLOR  LIQUIDS. 

IN  GLASS  BOTTLES. 


1620. — Carmine 

1621. — Indelible  Brown  Ink. 

1622.  — Prout’s  Brown  

1623. — Gold  Ink 

1624. — Extract  of  Ox  Gall. . . 


1625. — Indian  Ink 

1626. — Chinese  White 

1627. — Sepia 

1628. — Silver  Ink 

1629.  — Prussian  Blue  . 


35 

35 

45 

40 

35 


1630. — Pure  Gold  in  shells,  20  cents  ; in  cups,  25  cents ; in  cakes . . 2 00 

1631. — Silver  Cakes  in  shells,  15  cents  ; in  cups — 35 


WINSOR  & NEWTON’S  WATER  COLOR  BOXES. 


1635.  —Polished  Mahogany  Box,  with  lock  and  key,  and  drawer,  paint-stone, 

water-glass,  India  ink,  brushes,  and  12  colors,  whole  cakes  $9  00,  half  $6  00 

1636—  Do.  do.  do.  18  do.  do.  14  00  do.  8 00 

1637—  Do.  do.  do.  24  do.  do.  18  00 


W.  & L.  E.  GURLEY.  TROY,  X.  Y. 


293 


1635.— “Complete”  Box. 


INDIA  INK. 


The  Chinese  Inks  are  most  suitable  for  general  draughting. 
Japanese,  only  for  those  drawings  in  which  the  ink-lines 
frequently  washed  in  applying  water  colors. 


The 

are 


No. 

1650.  — Oval,  black,  Lion  head,  per  cake 

1651. — Round,  gilt,  do.  do 

1652.  — Round,  gilt,  Lion  head,  per  cake 

1653. — Hexagon,  gilt,  per  cake 

1654.  Square,  black.  Super  Super  (choice),  per  cake. . 

1655.  Do.  do.  do.  half  cake.. 

1656.  Blue,  Red,  and  Yellow  India  Ink,  each,  per  cake. 


Price 
...  $ 40 
25 
75 
50 

. 2 00 
1 00 
75 


JAPANESE  INK. 

1660.  Oblong,  black,  with  Figures,  best  small  cake,  per  cake 

1661. —  Do.  do.  do.  large  do 

These  Inks  are  imported  for  us  from  China  and  Japan. 
1665.— Higgins’  Waterproof  Drawing  Ink,  per  bottle 


W.  & L.  E.  GURLEY,  TROY,  K.  Y. 


INDIA  INK. 


(For  Prices,  see  pp.  293.) 


295 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


WATER  COLOR  BRUSHES. 


1670. — Camel  Hair  in  Quills, 

No.  1.  2.  3. 

each,  $ 05  05  06 


4.  5.  6.  7. 

06  08  08  10 


CO 


8. 

10 


1675. — Red  Sable  in  Quills, 

No.  1.  2. 

each,  $ 10  12 


3.  4. 

15  20 


5. 

25 


7.  8. 

35  40 


1670  and  1675. 


296 


W.  & L.  E.  GURLEY,  TROY,  N.  Y 


50 


1690.— Red  Sable  in  Albata,  with  handle, 

No.  1.  2.  3.  4.  5. 

each,  $ 25  30  40  50  60 


95 


13.  14. 

1 25  1 65 


6. 

70 


1685. 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


297 


1695. 


1695.— Camel  Hair  Wash  Brushes  in  Tin,  with  2 points, 

No.  0.  1.  2.  3. 

each,  $ 40  50  60  75 


1698.— Red  Sable  in  Albata,  with  2 points, 


No.  00. 

0. 

1. 

2. 

3x5 

4x6 

5x13 

7x15 

each,  $1  00 

1 25 

1 75 

3 00 

GILLOTT’S  STEEL  PENS. 

No.  Price 

1700. — Mapping,  on  cards,  per  dozen <£  75 

1701. — Lithograph,  on  cards,  per  dozen 75 

1702.  —Lithograph  Crow  Quill,  on  cards,  per  dozen . 75 

1703. -  Extra  Fine,  No.  303,  per  dozen,  $.20  ; per  gross 1 50 


1704-  Do.  170, 

do. 

.15: 

do 

1 25 

1705.— Falcon  Pens, 

do. 

.12; 

do 

1 00 

1706.— Commercial  Pens, 

do. 

.10: 

do 

75 

1707.— Business  Pens, 

do. 

.10; 

do 

SOENNECKEN’S  ROUND  WRITING  PEN. 


1709.— Single-pointed  Pens,  per  gross,  $1.10 ; per  dozen $ 20 

A.  — Double-pointed  Pens,  assorted,  per  dozen 50 

B. — Copy  Book,  without  instructions 60 

C- — Text  Book  for  Round  Writing,  giving  full  instructions  1 10 

D.—  Sample  assortment  of  Pens,  25  in  a box. 35 


298 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


LEAD  PENCILS. 


A.  W.  FABER?S. 

No.  Price 

1710. — Hexagon,  very  best  Siberian,  Nos.  4 B to  6 H,  per  dozen. $1  25 

1711.  — Do.  do.  Drawing,  Nos.  1 to  5,  do 75 

1712. — Black  round,  best,  Nos.  1 to  4,  do 60 

1713.  — Hexagon,  for  Divider  Points,  No.  4,  do 1 00 

1714. — Round,  do.  do.  do 75 


Artist  Pencil  ivith  Siberian  Lead. 


1715. 


1715. — Artist  Pencil  with  Siberian  lead,  each .$  35 

1716. -  Leads  for  Artist  Pencils,  Siberian,  6 in  box,  per  box 65 

These  leads  fit  the  new  pencil-holders  in  Alteneder  and  Swiss  sets. 

1717. — Round  red,  blue,  green,  and  yellow,  per  dozen 1 25 

1718. — One  box,  containing  5 pencils,  BB  to  H * 50 

1719. —  Do.  do.  7 do.  BBB  to  HH  65 

1720. —  Do.  do.  10  do.  BBBB  to  HHHH 90 

1725.  — Red  Chalk  Pencils  for  marking  stakes,  per  dozen 50 

1726. —  Do.  in  lump,  per  pound 15 

1727. — French  Venetian  Crayons,  for  marking  stakes  (superior  quality)  per 

dozen 60 


SPONGE  RUBBER. 


FOR  CLEANING  DRAWINGS. 

1730. — Sponge  Rubber,  medium  cakes,  each 

1731.  — Do.  large  do 


$ 40 
75 


1735. 


1742. 


w.  & L.  E.  GURLEY,  TROY,  N\  Y, 


290 


INDIA  RUBBER. 

No. 


1735.— A. 

W.  Faber’s  First  Quality,  white,  1%  x 1 inch,  each 

1736. — 

Do. 

do.  do.  IX  *1%  do. 

1737.— 

Do. 

do.  do.  2 x IX  do. 

1738.— 

Do. 

do.  do.  3 x2%  do. 

1740.- 

Do. 

do.  Black  pure  Gum,  2x1%  inch,  each 

1741.— 

Do. 

Improved  Ink  Eraser,  ly2  x 1 inch,  each. . 

1742.— 

Do. 

Combined  Ink  and  Pencil  Eraser,  each 

1743.— 

Do. 

d°-  do-  do.  Mammoth,  < 

Peicb 
$ 06 
12 
20 
50 
20 
05 
20 
30 


1744 


1744.— A W.  Faber’s  Pointed  Rubber,  2%  x & inches,  each. 
1745—  Do.  da.  3 x % do. 


1746. 


1746.- 

Davidson’s  Velvet  Rubber,  oblong:,  i5A  inch.  each.  . . 

1747.- 

Do, 

do. 

do.  2f4  x /jr  do 

12 

1748.- 

- Do. 

do. 

do.  3f4  x % do 

20 

1749.- 

- Do. 

do. 

do.  3 x 2J4  x do 

50 

STEEL  ERASERS. 


1750.  -Roger  & Son’s  Steel  Blade,  Cocoa  Handle, 

1751. —  Do.  do.  Ivory  do. 

1752. —  Do.  Knife  Eraser,  Ebony  do. 


each 
do.  . 
do.  . 


$ 50 
75 
75 


300 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


DRAWING  BOARDS. 

No.  Price 

1755. — 14  x 10  inches,  35  cts. ; 20  x 15  inches $ 75 

1756.  — Super  Royal  size,  tongue  and  groove  ends 1 25 

1757.  — Double  Elephant  size,  do.  2 50 

1759. — Framed  Drawing  Board,  Mahogany,  centre  soft  Pine  and  removable, 

17x12  inches 3 00 

1760.  — Do.  do.  do.  27x19  inches 5 00 

1761. — Drawing  Table,  black  walnut  top,  22  by  26  inches,  instrument  shelf 

7 by  26  inches,  two  instrument  drawers,  ornamented  iron  stand, 
mounted  on  castors,  each 12  50 

1762. — Similar  to  No.  1761,  top  of  selected,  polished  walnut,  iron  stand,  bronzed 

and  tastefully  ornamented 15  50 


These  tables,  suitable  for  architects1  offices,  counting-rooms,  &c.,orfor 
home  use,  can  be  readily  fixed  at  any  height  from  30  to  44  inches,  with 
the  top  horizontal,  vertical,  or  inclined  at  any  angle,  while  the  instru- 
ment shelf  and  drawers  always  remain  level.  In  any  of  these  posi- 
tions the  top  can  be  allowed  to  rotate,  or  the  whole  firmly  clamped. 
Total  weight,  55  pounds. 


MISCELLANEOUS. 


1775. — Best  Foolscap  Paper,  per  ream,  $5  00  ; per  quire $ 35 

1776. — Best  Letter  Paper,  do.  4 50  ; do 30 

1777 —Best  Commercial  Note,  do.  2 75  ; do 20 

1778._SUperior  Post  Office  Paper,  buff  tint,  24  x 19,  per  ream,  $7  50;  per  quire  50 

1780. — Specification  Paper,  extra  fine  Legal  Cap.  thick,  do.  5 75 ; do.  40 

1781. — Flat  Paper,  smooth,  extra,  21  x 16,  per  ream,  $9  50  ; per  quire 60 

1782. —  Do.  do.  do.  23  x 18,  do.  15  00 ; do.  90 

1783. — Superior  White  Envelopes,  per  thousand 4 00 

1784. —  Do.  Buff  do.  do.  3 50 

1785. —  Do.  do.  do.  “ legal”  (large  size),  per  thousand 7 00 

1786. — Arnold’s  Writing  Fluid,  per  quart — 75 

1789. — David’s  Carmine,  2 ounce  bottles,  per  bottle 50 

1790. — Rubber  Bands,  14  inch  wide,  2 inches  long,  per  gross,  $ 90 ; per  dozen  12 

1792.—  Do.  14  do.  3 do.  do.  1 35;  do.  20 

1795. —  Do.  % do.  2 14  do.  do.  2 00 ; do.  30 

1796.  — Do.  y2  do.  3 do.  do.  2 25;  do.  35 

1799. — Do.  Jo  do.  1J4  do.  for  tickets,  &c.,  per  gross. . 25 


All  other  sizes  Rubber  Bands  furnished  at  proportional  rates. 


1800. — Mucilage,  per  cone  (3  oz.) 

1801. —  Do.  quart 

1802. — Handy  Paper-Cutter,  Brass,  each 


W.  & L.  E.  GURLEY,  TROY,  N.  Y. 


301 


No.  Price 

This  little  instrument  is  of  important  service  to  Draughtsmen,  for  cut- 
ting drawings  from  the  board,  also  for  cutting  any  kind  of  paper  or 
Bristol  board.  It  is  slid  along  the  ruler  or  T Square  without  injuring 
the  edge,  as  is  done  by  using  a common  knife.  The  cutter  is  adjusted 
by  the  side  screw  to  cut  only  the  thickness  of  the  paper,  without 
striking  the  Drawing-board. 

Copying  Books,  Copying  Ink  and  Presses,  Blotting  Paper,  and  all 
articles  of  Stationery  needed  in  Engineers’  offices  furnished  at  reason- 
able rates. 

Envelopes,  Letter  and  Note  Heads,  Cards,  &c.,  printed  and  lithographed 
at  usual  prices. 

1805. — A.— Arkansas  Oil  Stones,  fine  quality,  4 to  6 inches  long $1  00  to  $2  50 

B. — Do.  do.  do.  for  Drawing  Pens,  Needles,  &c.  25 

1806. — A.— Washita  Oil  Stones,  fair  quality,  4 to  6 in.  long .50  to  1 25 

B. — Do.  do.  do.  for  Drawing  Pens,  &c. . . 15 

1807. — A — Brass  Blow  Pipes,  plain,  9 to  12  inches.  25  to  50 

B.—  Do.  do.  with  bulb,  do 50  to  75 

1808. — Carpenters  and  Masons’  Spirit  Levels,  plain  and  adjustable,  wood  body, 

brass  mounted,  18  to  30  inches  long 75  to  5 00 

1809 —Machinists'  Tools,  Lathe  and  Drill  Chucks  and  Drills,  Steel  Squares 
and  Gauges,  Brass  Tubing  and  Wire,  Sheet  Brass  and  German  Silver, 
Stubb’s  Steel  Wire,  &c.,  &c.,  at  Manufacturers’  prices. 

1810.— A — Thermometers,  Japanned  cases 25  to  1 50 

B.  — Do.  Fancy  Wood  backs 1 00  to  3 00 

C. —  Do.  self-registering,  maximum  or  minimum,  each  3 00  to  5 00 

1815.— Hydrometers,  for  testing  Spirits,  Ammonia,  Ether,  Alkalies,  Vinegar, 

Molasses,  Salt  Water,  Urine,  Milk,  Oils,  Beer,  Bark,  Ac 75  to  2 

Twaddel’s  Hydrometers,  Nos.  1 to  5,  each 1 

1820.— Smithsonian  Rain  Gauge,  made  entirely  of  brass.  This  gauge  has  beep 
adopted  by  the  Smithsonian  Institute  and  U.  S.  Patent  Office,  and  is 
the  most  simple  in  its  construction  of  any  now  in  use.  It  is  furnished 
with  a graduated  scale  which  reads  to  lOths  and  lOOths  of  inches : also 
a wooden  cylinder  to  insert  in  the  ground  for  the  protection  and  ready 
adjustment  of  the  instrument 5 00 


8 8 


W.  & L.  E.  G-URLEY’S 


Book  Circular, 


18  8 4. 

ARCHITECTURE,  BRIDGES,  CIVIL 
SURVEYING,  CONSTRUCTION, 
OF  MATERIALS,  GEOLOGY, 

ENGINEERING, 

STRENGTH 

MINING, 

POCKET  BOOKS,  TABLES, 
INSTRUMENTS,  ETC. 


NOTE. — Parties  ordering  should  either  send  drafts  on  New 
York,  or  postal  orders  on  Troy,  N.  Y. ; or  if  money  is  enclosed  in 
letters,  such  letters  should  be  registered  at  the  post-office  where 
mailed. 

We  prepay  postage  on  nearly  all  American  and  English  Books 
when  the  price  is  sent  to  us  in  advance. 

Orders  for  over  $10,  will  be  sent  by  express  “C.  O.  D.;”  but 
for  smaller  sums  parties  will  please  remit  the  necessary  amount 
with  their  order. 

Write  all  letters  legibly,  give  your  Post-office,  County,  and 
State,  and  be  sure  to  sign  your  letter  before  mailing. 

We  are  not  responsible  for  loss  of  goods  sent  by  mail. 

Should  any  other  works  on  kindred  topics  be  desired,  we  will 
furnish  them  at  publishers’  prices. 


PUBLISHED  BY  W. 


& L.  E.  GURLEY, 


TROY,  N.  Y. 


304 


w.  & l.  e.  gurley’s  list  of  books. 


ARCHITECTURE,  CARPENTRY,  AND  BUILDING. 

Price 

ALLEN,  L.  F.  Rural  Architecture  ; being  a Complete  Description  of  Farm- 

Houses,  Cottages,  and  Out-Buildings $1  50 

BLENKARN,  J.  Practical  Specifications  of  Works  executed  in  Architecture, 

&c.  8vo.  London 9 00 

BROOKS,  S.  H.  Erection  of  Dwelling  Houses,  with  Specifications,  Quantities 

of  Materials,  &c.  27  plates.  (Weale’s  series.) 100 

BULLOCK,  J.  Rudiments  of  Architecture  and  Building.  250  engravings. 

8vo 3 

“ American  Cottage  Builder.  75  engravings.  8vo 3 

BURN,  R.  S.  Practical  "Ventilation.  12mo.  Edinburgh 2 

CUMMINGS,  M.  F.  Architectural  Details.  1 vol.  large  4to.  6 

DICTIONARY  of  Terms,  used  by  Builders,  Architects,  &c 2 

DOBSON,  E.  Foundations  and  Concrete  Works.  (Weale’s  series ) 

u The  Art  of  Building.  (Weale’s  series.) 

“ Masonry  and  Stone  Cutting.  (Weale’s  series.) . ...  1 

DOWNING,  A.  J.  Cottage  Residences.  4to 5 

“ Architecture  of  Country  Houses.  8vo 6 

“ A Treatise  on  Landscape  Gardening  and  Rural  Architec- 
ture. Thick  8vo.  Finely  illustrated 6 

GILLMORE,  Gen.  Q.  A.  A Practical  Treatise  on  Coignet  Beton  and  other 

Artificial  Stones.  8vo.  With  numerous  plates 2 

GOTHIC  Stone  Work.  With  Plates 1 

GOULD,  L.  D.  American  Stair  Builder’s  Guide.  8vo.  Illustrated 3 

u Carpenters’  and  Builders’  Assistant,  and  Wood  Workers’ 

Guide.  8vo.  Illustrated 2 

HATFIELD,  R.  G.  The  American  House-Carpenter.  Eighth  edition.  8vo.  5 
HOLLEY,  H.  H.  Country  Seats,  containing  Designs  for  Cottages,  Villas, 

Mansions,  Railway  Stations,  &c.  4to 5 

LEEDS,  L.  W.  Lectures  on  Ventilation.  New  York.  8vo 1 

LEUCHARS,  R.  B.  How  to  Build  and  Ventilate  Hot-Houses.  Illus.  12mo.  1 

MODERN  Architectural  Designs  and  Details.  4to.  Finely  Illustrated 10 

PALLISER’S  Model  Homes,  showing  a Variety  of  Designs  for  Model  Dwell- 
ings. 8vo.  Cloth 1 

REID,  H.  A practical  Treatise  on  Concrete,  and  How  to  Make  it.  With 

Observations  on  the  Use  of  Cements,  Limes,  and  Mortars.  8vo 6 

SMITH,  T.  R.  Acoustics'of  Public  Buildings.  (Weale’s  series.) 

TREDGOLD  & TARN.  Carpentry  and  Joinery.  With  Plates.  (Weale’s 

Series.)  2 vols 3 

TUTHILL,  W.  B.  Interiors  and  Interior  Details.  4to  Illustrated 7 

“ Practical  Lessous  in  Architectural  Drawing.  8vo.  Illus.  2 

VAUX,  C.  Villas  and  Cottages.  With  nearly  500  engravings.  8vo 3 

WARREN,  S.  E.  Stereotomy.  Problems  in  Stone  Cutting.  8vo 2 

WHEELER,  G.  Rural  Homes,  or  Sketches  of  Houses  suited  to  American 

Country  Life.  12mo.  New  York 150 


8880“  §8  8 8888  88  888  8 8888ggg8gg 


W.  & L.  E.  GURLEY’S  LIST  0?  BOOKS.  305 

Price 


WHEELER,  G.  Homes  for  the  people  in  Suburb  and  Country,  the  Villa,  the 
Mansion,  and  the  Cottage,  adapted  to  American  Climate  and  Wants. 

Revised  edition.  12mo.  New  York $2  00 

WOODWARD,  G.  E.  Country  Houses.  12mo 100 

“ Cottage  and  Farm  Houses.  With  178  original  Designs 

and  Plans  of  low-priced  Cottages  and  Farm  Houses.  1 00 
“ National  Architect.  A very  complete  work.  Fully 

illustrated.  2 vol.  4to.  Each 7 50 

“ Rural  Church  Architecture  ; containing  18  Designs  by 

different  Architects 4 00 

“ Suburban  and  Country  Houses.  With  70  Designs  and 

Plans,  and  numerous  examples  of  the  French  or 

Chateau  Roof 1 00 

WOOLLETT,  W.  M.  Old  Homes  made  new.  Illus.  Oblong 150 

v‘  Villas  and  Cottages  ; or,  Homes  for  all.  8vo 3 00 


ASTRONOMY. 


ASTRONOMY.  R.  Main.  (Weale’s  series.) $ 60 

CHAUVENET,  WM.  A Manual  of  Spherical  and  Practical  Astronomy ; its 
Special  Application  to  Nautical  Astronomy,  and  the  Theory  and  Use  of 

Fixed  Astronomical  Instruments.  2 vols.  royal  8vo.  Phila 6 00 

GLAZEBROOK,  R.  T.  Physical  Optics.  430  pp 2 


GUILLEMIN,  A.  The  Heavens.  A Hand-book  of  Popular  Astronomy.  8vo.  4 
LOOMIS,  E.  Practical  Astronomy,  with  a collection  of  Astronomical  Tables. 
This  work  furnishes  a description  of  the  instruments  required  in  the  out- 
fit of  an  observatory,  as  also  the  methods  of  employing  them,  and  the 
computations  growing  out  of  their  use.  Of  the  method  of  determining 
time,  latitude,  and  longitude,  with  the  computation  of  eclipses  and  occul- 
tations.  The  work  is  designed  for  the  use  of  amateur  observers,  practical 


surveyors,  and  engineers.  8vo 2 00 

NAUTICAL  Almanac.  Published  by  authority  of  the  Secretary  of  the  Navy. 

Washington.  Each  year 75 

and  Ephemeris.  Each  year 1 25 

NEWCOMB,  S.  Popular  Astronomy.  8vo.  Illustrated  2 50 

NORTON.  W.  A.  Treatise  on  Astronomy— Spherical  and  Physical.  8vo 3 50 

PROCTOR,  R.  A.  Half-Hours  with  the  Telescope.  12mo.  Illustrated 1 25 

Half-Hours  with  the  Stars.  A plain  and  easy  guide  to  the 
knowledge  of  the  constellations,  with  separate  explana- 
tion of  each  map.  True  for  every  year.  Demy  4to 2 25 

STEELE.  Fourteen  Weeks  in  Astronomy — 1 50 

YOUNG,  J.  R.  Nautical  Astronomy  and  Navigation.  (Weale’s  series.) 1 00 

Navigation  Tables.  (Weale’s  series.) 60 


g S 


306 


W.  & L.  E.  GURLEY’S  LIST  OF  BOOKS. 


BRIDGES,  ROOFS,  &c. 

Price 

BAKER,  B.  Long-Span  Railway  Bridges $2  00 

BASHFORTH,  F.  A Practical  Treatise  on  the  Construction  of  Oblique 

Bridges,  with  spiral  and  equilibrated  courses.  With  12  plates.  8vo 4 50 

BLAND,  W.  Arches,  piers,  buttresses.  (Weale’s  series.) 60 

BOLLER,  A.  P.  Practical  Treatise  on  the  Construction  of  Iron  Highway 
Bridges  ; with  a short  essay  upon  the  Application  of  the  Principles  of  the 
Lever  to  a ready  Analysis  of  the  Straius  upon  the  more  customary  form 

of  Beams  and  Trusses.  Illustrated.  8vo 2 50 

BUCK,  G.  W.  A Practical  and  Theoretical  Essay  on  Oblique  Bridges.  2d 

edition.  Corrected  by  W.  H.  Barlow.  8vo 4 50 

BURR,  WM.  H.  Stresses  in  Bridges  and  Roof  Trusses.  8vo.  cloth 3 50 

CAMPIN,  F.  Construction  of  Iron  Roofs  2 00 

CULLUM,  G.  W.  System  of  Military  Bridges  in  the  United  States  and 

Europe.  8vo.  With  Plates 3 50 

DEMPSEY,  G.  D.  Iron  Applied  to  Railway  Structures,  with  practical  notes 
and  illustrated  plates  and  descriptions  of  some  of  the 
principal  Railway  Bridges.  4to,  with  plates.  London. 

Paper 1 50 

“ Tubular  and  Iron  Girder  Bridges,  including  the  Britannia 

and  Conway  Bridges.  (Weale’s  series  ) — 60 

DOWLING,  C.  H.  Iron  Work.  Practical  Formulae  and  Rules  for  finding  the 

Strain  and  Breaking  Weight  of  Wrought  Iron  Bridges.  16mo  ...  40 

GREENE,  C.  E.  Roof  Trusses.  8vo 125 

“ Bridge  Trusses.  8vo 2 50 

“ Arches.  Wood,  Iron,  and  Stone.  8vo 2 50 

HAUPT,  H.  Bridge  Construction.  With  practical  illustrations.  8vo 3 50 

“ Military  Bridges ; Designs  for  Trestle  and  Truss  Bridges. 

8vo 6 50 

HENRICI,  O.  Skeleton  Structures.  In  their  application  to  Steel  and  Iron 

Bridges,  with  folding  plates.  8vo 1 50 

MERRILL,  W.  E.  Iron  Truss  Bridges  for  Railways.  With  a comparison  of 

the  most  prominent  Truss  Bridges.  Illustrated.  4to 5 00 

ROEBLING,  J.  A.  Long  and  Short  Span  Raihvay  Bridges.  With  16  fine 

copper  Plates  Folio 25  00 

SHREYE,  S.  H.  Strength  of  Bridges  and  Roofs.  89  cuts.  8vo,  tinted 3 50 

WHIPPLE,  S.  Bridge  Building.  4th  Ed.,  1883.  8vo  4 00 

WOOD,  DE  VOLSON.  Treatise  on  the  theory  of  the  Construction  of  Bridges 

and  Roofs.  8vo 2 00 


W.  & L.  E.  GUKLEY’S  LIST  OF  BOOKS.  307 

CHEMISTRY,  PHYSICS,  &c. 

Price 

ATWOOD,  GEO.  Practical  Blow-Pipe  Assaying.  12mo,  illustrated $2  00 

ATTFIELD,  J.  Chemistry,  General,  Medical,  and  Pharmaceutical.  12mo..  2 50 
BAYLEY,  THOS.  A Pocket-book  for  Chemists,  Chemical  Manufacturers, 

Metallurgists,  Dyers,  Distillers,  Brewers,  &c.  32mo,  oblong.. 2 00 

BOOTH  and  MORFIT.  Encyclopedia  of  Chemistry,  Practical  and  Theoreti- 
cal. Royal  8vo 5 00 

CHURCH  A.  H.  The  Laboratory  Guide  ; Practical  Chemistry  for  Colleges 

and  Schools,  especially  arranged  for  Agricultural  Students.  12mo 2 50 

DE  KONN1CK  & DIETZ.  Manual  of  Chemical  Analysis  and  Assayings. 

Edited  by  Rob.  Mallet.  12mo 2 50 

FOWNES,  PROF.  GEO.  Chemistry,  for  use  of  Farmers.  (Weale’s  series.)..  60 
GANOT- ATKINSON.  Elementary  Treatise  on  Physics,  experimental  and 

applied.  8vo 5 00 

MOTT,  H.  A.,  Jr.  Chemist’s  Manual.  A Practical  Treatise  on  Chemistry, 
Assaying,  Blowpipe  Analysis,  Mineralogy,  Specific  gravities,  &c.  New 

Edition,  1883  4 00 

MUSPRATT,  DR.  S.  Chemistry  applied  to  Arts  and  Manufactures,  with 

1,000  engravings  on  wood.  London.  Complete,  2 vols,  8vo 24  00 

PEPPER,  J.  H.  The  Boy’s  Play-Book  of  Science,  including  the  various 
Manipulations  of  Chemical  and  Philosophical  Apparatus  required  for 

Scientific  Experiments.  New  edition,  illustrated.  12mo 2 00 

PLATTNER,  T.  H.  Blowpipe  Analysis.  4th  edition,  illus.  560  pp.,  8vo 5 00 

PRESCOTT,  A.  B.  First  Book  in  Qualitative  Chemistry.  12mo 1 50 

PYNCHON,  T.  R.  Chemical  Physics.  Designed  for  use  in  Academies  and 

High  Schools.  New  edition.  Crown  8vo 3 09 

REGNAULT,  M.  V.  Elements  of  Chemistry.  Translated  from  the  French 
by  T.  Forrest  Betton,  M.D , and  edited,  with  Notes,  by  James  C.  Booth, 

Melter  and  Refiner  IT.  S.  Mint,  and  Wm.  L.  Faber,  Metallurgist  and 
Mining  Engineer.  Illustrated  by  nearly  700  wood  engravings.  Two 

volumes,  8vo 7 50 

SILLIMAN,  BENJ.  First  Principles  of  Chemistry.  12mo 2 00 

“ First  Principles  of  Physics  or  Natural  Philosophy.  8vo.  3 50 

STEELE.  Fourteen  Weeks  in  Chemistry 150 

WELLS,  DAVID  A.  Principles  and  Applications  of  Chemistry,  for  the  Use 

of  Schools,  Academies,  and  Colleges 1 75 

YOUMANS,  E.  L.  Class-Book  of  Chemistry.  12mo.  New  edition 1 75 


308  W.  & L.  E.  GURLEY’S  LIST  OF  BOOKS. 

CONSTRUCTIONS,  STRENGTH  OF  MATERIALS,  &c. 

Price 

BARBA,  J.  The  Use  of  Steel  in  Construction.  Methods  of  Working,  Apply- 
ing, and  Testing  Plates  and  Bars.  12mo.  Illustrated $1 

BARLOW,  P.  On  the  Strength  of  Materials.  New  edition,  enlarged.  8vo..  7 
BURR,  WM.  H.  Elasticity  and  Resistance  of  the  Materials  of  Engineering. 

8vo 5 00 

BURNELL,  G.  R.  Limes,  Cements,  and  Mortars.  (Weale’s  series.) CO 

EASTON,  ALEX.  Horse  Railways;  their  Location,  Construction,  and  Man- 
agement. 8vo 3 00 

FAIRBAIRN,  WM.  Application  of  Cast  and  Wrought  Iron  for  Building 

Purposes.  8vo... 2 00 

GILLMORE,  GEN.  Q.  A.  Treatise  on  Limes,  Hydraulic  Cements,  and  Mor- 
tars. Papers  on  Practical  Engineering,  U.  S. 
Engineer  Department.  With  numerous  illus- 
trations. 8vo 4 00 

“ Report  on  Strength  of  the  Building  Stones  in  the 

United  States,  &c.  8vo,  illustrated 1 00 

IIATFILLD,  R.  G.  Theory  of  Transverse  Strains,  and  its  application  to  the 

construction  of  Buildings,  Iron  Girders,  Roofed  Trusses,  &c.  8vo 5 00 

HUNTINGTON,  W.  S.  Roadmaster’s  Assistant  and  Sectionmaster’s  Guide.  1 50 

JERVIS,  J.  B.  Railway  Construction  and  Management.  12mo 2 00 

LAW  & CLARK.  Construction  of  Roads  and  Streets.  (Weale’s  series.) 180 

MAHAN,  PROF.  D.  H.  Fortifications  and  Stone-Cutting,  Descriptive  Geome- 
try applied  to  the  Drawing  of.  8vo,  plates. 1 50 

“ Mechanical  Principles  of  Engineering  and  Architec- 

ture. By  H.  Mosely.  Edited  with  Additions,  by 

Prof.  L.  H.  Mahan.  8vo 5 00 

“ Field  Fortification.  A Treatise  on.  Illustrated.  8vo.  3 50 

SHIELDS,  J.  E.  Notes  on  Engineering  Construction , and  description  of  the 
materials  employed  in  Tunneling,  Bridging,  Canal  and  Road  Building,  &c. 

Illustrated,  12m  o 1 50 

STEVENSON,  THOS.  Lighthouses,  their  Construction  and  Illumination. 

(Weale’s  series.) 1 20 

STONEY,  B.  B.  The  Theory  of  Strains  in  Girders  and  similar  structures. 

With  observations  on  the  application  of  Theory  to  Practice,  tables  of 

strength  of  materials,  &c.  New  edition,  complete,  1 vol.  8vo 12  50 

WEYRAUCH,  J.  J.  Strength  and  Calculations  of  Dimensions  of  Iron  and 
Steel  Construction,  with  reference  to  the  Latest  Experiments.  12mo, 

plates  1 

WOOD,  DE  VOLSON.  Resistance  of  Materials,  and  an  appendix  on  the  Pre- 
servation of  Timber.  This  book  contains  the  theory  of  the  strength  of 
materials,  theories  of  flexure  aud  rupture  from  tranverse  stress,  and  the 
limits  of  safe  loading  for  mechanical  structures,  etc.  8vo 3 00 


g g 


W.  & L.  E.  GURLEY’S  LIST  OE  BOOKS.  309 

DRAWING. 

Price 

ANDRE,  G.  G.  Draughtsman’s  Hand-book  of  Plan  and  Map  Drawing.  8vo.  $3  75 

APPLETON’S  Cyclopedia  of  Drawing.  New  edition,  enlarged 10  00 

BECKER’S  Letter  Book.  A series  of  Analytical  and  Finished  Alphabets — 4 00 

CHURCH,  A.  E.  Elements  of  Descriptive  Geometry,  with  its  Applications 
to  Spherical  Projections,  Shades,  and  Shadows,  Perspective  and  Isometric 
Projections.  8vo,  and  atlas  of  plates,  4to.  Text-Book  at  West  Point 

Mil.  Academy,  and  Rensselaer  Polytechnic  Institute 4 00 

COPLEY,  F.  S.  A Set  of  Alphabets  of  all  the  Various  Hands  of  Modern  Use, 
with  Examples  in  each  Style ; also,  the  Mechanical  and  Analytical  Con- 
struction of  Letters,  Figures,  and  Titles 3 

DAVIES,  C.  Treatise  on  Shades  and  Shadows,  and  Linear  Perspective.  8vo.  3 

ESSER.  Draughtsman’s  Alphabets 2 

REAM,  P.  A Hand-Book  of  Map  Drawing.  Small  quarto 

MAHAN,  D.  H.  Industrial  Drawing  ; comprising  the  Description  and  Uses 

of  Drawing  Instruments,  &c.  1 vol.  and  atlas,  8vo 3 

MAXTON,  J.  Workman’s  Manual  of  Engineering  Drawing.  12mo 1 

McLEES,  A.  Alphabets  and  Fancy  Letters.  Text-book  for  Engineers  and 

Sign  Painters.  Small  oblong 1 

MINIFIE,  WM.  Mechanical  Drawing,  including  an  Introduction  to  Iso- 
metrical  Drawing,  and  an  Essay  on  Linear  Perspective . 

and  Shadows.  Finely  illustrated.  8vo 4 

“ Geometrical  Drawing — an  abridgment  of  the  above.  New 

edition 2 

PYNE,  GEO.  Perspective.  (Weale’s  series.) 

RUSKIN.  Elements  of  Perspective  ; arranged  for  the  use  of  Schools 1 

“ Elements  of  Drawing  ; in  three  letters  to  Beginners.  Illustrated.  1 

SMITH,  R.  S.  Manual  of  Topographical  Drawing.  8vo.  Plates  . . 2 

VOSE,  G.  L.  An  Elementary  Course  of  Geometrical  Drawing.  Containing 
Problems  on  the  Right  Line  and  Circle,  Conic  Sections  and  Other  Curves ; 
the  Projection,  Section,  and  Intersection  of  Solids ; the  Development  of 

Surfaces,  and  Isometric  Perspective.  With  38  plates 6 

WARREN,  S.  E.  Free-Hand  Drawing  (with  plates).  12mo 1 

Drafting  Instruments  and  Operations.  12mo 1 

“ Manual  of  Projection  Drawing.  12mo 1 

“ Manual  of  Linear  Perspective.  12mo  1 

“ Plane  Problems  in  Elementary  Geometry.  12mo 1 

Elements  of  Descriptive  Geometry.  8vo. 3 

Elements  of  Machine  Construction  and  Drawing.  8vo, 

with  plates 7 

General  Problems  of  Shades  and  Shadows.  8vo 3 

“ Higher  Linear  Perspective.  8vo 3 

WILLIAMS  & PACKARD’S  Ornamental  Letter  Book 5 

WOODWARD’S  Alphabets.  Each,  $.50;  or  complete  in  one  vol.  quarto, 

Cloth ; G 00 


8S8S  8S8S88  8 88888  8 8 $g  8 8 B 8 


310 


W.  & L.  E.  GURLEY’S  LIST  OF  BOOKS. 


ELECTRICITY,  TELEGRAPHY,  &c. 

Price 

AIRY,  G.  B.  A Treatise  on  Magnetism,  designed  for  the  use  of  students  in 

the  University.  Illustrated.  12mo.  London $3  00 

CLARK  (Latimer)  and  Sabine  (Robert).  Electric  Tables  and  Formula  for  the 

use  of  Telegraph  Inspectors  and  Operators.  Illustrated.  12mo 5 00 

CULLEY,  R.  S.  Hand-book  of  Practical  Telegraphy.  7th  edition.  8vo 6 00 

DESCHANEL,  A.  P.  Elementary  Treatise  on  Natural  Philosophy,  Electric- 
ity, and  Magnetism,  illustrated  by  241  engravings.  8vo 5 00 

DOLBEAR,  E.  A.  The  Telephone.  An  Account  of  the  Phenomena  of  Elec- 
tricity, Magnetism,  and  Sound,  as  involved  in  its  Action,  with  Directions 

for  making  a Speaking  Telephone.  Illustrated 50 

HARRIS,  SIR  W.  S.  A Treatise  on  Frictional  Electricity,  in  Theory  and 

Practice.  London,  8vo 7 00 

“ Magnetism  ; being  a Concise  Exposition  of  the  Gen- 

eral Principles  of  Magnetic  Science,  &c.  (Weale’s 

series.) 1 80 

JECKEN,  J.  F.  Treatise  on  Light,  Color,  Electricity,  and  Magnetism  8vo.  2 50 
KEMPE,  H.  H.  Hand-book  of  Electrical  Testing.  New  edition,  1881.  12mo.  5 00 

LARRABEE,  CHAS.  Cipher  Letter  and  Telegraphic  Code.  12mo. 1 00 

LOCKWOOD,  T.  D.  Electricity,  Magnetism,  and  Electric  Telegraphy.  A 
Practical  Guide  and  Hand-Book  of  General  Information  for  Electrical 
Students,  Operators,  and  Inspectors.  Octavo,  378  pages,  152  illustrations.  2 50 
McGREGOR,  W.  Questions  on  Magnetism,  Electricity,  and  Practical  Mag- 
netism. (Weale’s  series.) 60 

NO  AD,  H.  M.  Student’s  Text-Book  of  Electricity.  8vo 4 00 

POPE,  F.  L.  The  Modern  Practice  of  the  Electric  Telegraph.  9th  edition. 

8vo.  New  York 2 00 

PRESCOTT,  G.  B.  The  Speaking  Telephone,  Electric  Light,  and  other  recent 

Electrical  Inventions.  8vo.  Illustrated 4 00 

“ Electricity  and  the  Electric  Telegraph.  8vo.  Illustrated.  5 00 

SAWYER,  W.  E.  Electric  Lighting  by  Incandescence,  and  its  application  to 

interior  illuminations.  8vo 2 50 

SPRAGUE,  J.  T.  Electricity  ; its  Theory,  Sources,  and  Applications.  New 

edition.  8vo 3 00 

URQUHART,  J.  W.  Electric  Light;  its  Production  and  Use,  embodying 
Plain  Directions  for  the  Working  of  Galvanic  Batter- 
ies, Electric  Lamps,  and  Dynamo-Electric  Machines. 

Edited  by  C.  F.  Webb.  8vo,  with  94  illustrations. 

London,  1880 3 00 

“ Electro-Motors.  A Treatise  on  the  Means  and  Appa- 

ratus Employed  in  the  Transmission  of  Electrical 
Energy  and  its  Conversion  into  Motive  Power.  12mo, 

Illus,  London,  1882 3 00 


W.  & l.  e.  GUiiLEY’s  List  oj?  books.  Bll 

GEOLOGY,  MINING,  AND  METALLURGY. 

Price 

BAUERMAN,  H.  Metallurgy  of  Iron.  Containing  Outlines  of  the  History 
of  Iron  Manufacture,  Analysis  of  Iron  Ores,  &c.  5th  edition,  1882. 

12mo $2  00 

BLAKE,  W.  P.  The  Production  of  the  Precious  Metals ; or  Statistical 
Notices  of  the  Principal  Gold  and  Silver  Producing  Regions  of  the 

World.  8vo 2 00 

BODEMANN,  T.  Treatise  on  the  Assaying  of  Lead,  Silver,  Copper,  Gold, 

and  Mercury.  12m  2 50 

BYRNE,  O.  The  Practical  Metal-worker’s  Assistant.  600  engravings.  8vo.  7 00 

COLLINS,  J.  H.  Mining  and  Quarrying,  (Weale’s  series.) 60 

CROOKES,  WM.  A Practical  Treatise  on  Metallurgy.  Adapted  from  the 
last  German  edition  of  Prof.  Kerl’s  Metallurgy.  In  three 

vols.  thick  8vo 30  00 

Separately.  Vol.  I,  Lead,  Silver,  Zinc,  Cadmium,  Tin, 
Mercury,  Bismuth,  Antimony,  Nickel,  Arsenic,  Gold, 

Platinum,  and  Sulphur 10  00 

Vol.  2.  Copper  and  Iron 10  00 

Vol.  3.  Steel.  Fuel,  and  Supplement 10  00 

DANA,  J.  D.  Manual  of  Geology,  treating  especially  of  American  Geolog- 
ical History.  1881.  8vo 4 50 

“ Manual  of  Mineralogy,  including  Observations  on  Mines,  the 

Reduction  of  Ores,  &c.  12mo 2 00 

“ Text-book  of  Geology.  12mo 1 75 

“ A System  of  Mineralogy.  Descriptive  Mineralogy,  comprising 

the  most  recent  Discoveries.  1883.  Illustrated.  8vo 10  00 

FAIRBAIRN,  WM.  Iron  : its  History,  Properties,  and  Processes  of  Manu- 
facture   4 50 

LAMBORN.  R.  H.  Metallurgy  of  Copper.  (Weale’s  series.) 80 

“ Metallurgy  of  Silver  and  Lead.  Illustrated.  (Weale’s 

series.)  (Reprinting.) 

LYELL,  SIR  CHAS.  Principles  of  Geology ; or,  the  Modern  Changes  of 
the  Earth  and  its  Inhabitants  considered  as  illus- 
trative of  Geology.  Tenth  and  revised  edition. 

2 vols 12  00 

“ Elements  of  Geology.  8vo  3 50 

MACFARLANE,  JAS.  The  Coal  Regions  of  America ; their  Topography, 

Geology,  and  Development.  8vo 5 00 

MATHER,  JAMES.  The  Coal  Mines,  their  Dangers  and  means  of  Safety 10  00 

OVERMAN,  F.  Practical  Mineralogy,  Assaying,  Mining,  &c.  12mo 1 00 


312 


W.  & L.  E.  GURLEY’S  LIST  OF  BOOKS. 


Price 


OVERMAN,  F.  A Treatise  on  Metallurgy ; Comprising  Mining  ancl  Metal- 
lurgical Operations.  372  wood  engravings.  8vo $5  00 

PEPPER,  J.  H.  Play  Book  of  Metals,  including  Narratives  of  Visits  to  Coal, 

Lead,  Copper,  and  Tin  Mines.  8vo 2 25 

PHILLIPS,  J.  S.  Explorers  and  Assayers  Companion.  Vol.  1,  Rocks,  Veins, 

Testing  and  Assaying.  8vo.  San  Francisco — 6 00 

Vol.  2,  Mining  and  Metallurgy.  (In  preparation.) 

SMYTH,  W.  W.  Coal  and  Coal  Mining.  12mo.  (Weale’s  series.) 140 

STEELE.  Fourteen  Weeks  in  Geology 1 50 

VAN  WAGENEN,  T.  F.  Manual  of  Hydraulic  Mining,  for  the  Use  of  the 

Practical  Miner.  16mo 1 00 


HYDRAULIC  AND  SANITARY  ENGINEERING. 


ADAMS,  J.  W.  Sewers  and  Drains  for  Populous  Districts.  Embracing  Rules 
and  Formulas  for  the  dimensions  and  construction  of  works  of  Sanitary 

Engineers.  Second  edition.  8vo $2  50 

BAYLES,  J.  C.  House  Drainage  and  Water  Service  in  Cities  and  Towns. 

8vo 3 00 

BOX,  THOS.  Practical  Hydraulics  ; a series  of  rules  and  tables  for  the  use  of 

engineers,  &c.  12mo 2 00 

DEMPSEY.  Draining  Districts  and  Lands.  (Weale’s  series.)  (Reprinting.) 

“ Drainage  and  Sewerage  of  Towns  and  Buildings.  (Weale’s 
series.)  (Reprinting.) 

FANNING,  J.  T.  A Practical  Treatise  on  Water  Supply  Engineering;  relat- 


ing to  the  Hydrology,  Hydrodynamics,  and  Practical  Construction  of 


Water-works,  in  North  America.  8vo.  180  illustrations 5 00 

FRENCH’S  Principles,  Process,  and  Effects  of  Draining  Lands.  12mo 1 50 

FRISI,  P.  Rivers  and  Torrents,  and  a treatise  on  Navigable  Canals  and 

Rivers  that  carry  sand  and  mud.  (Weale’s  series.) 1 00 

GLYNN,  J.  Water  Power  as  applied  to  Mills.  12mo 100 

HEWSON,  WM.  Embanking,  Rivers,  Levees,  &c.  8vo 2 00 

HUGHES,  S.  Waterworks  for  Cities  and  Towns.  (Weale’s  series.) 160 

KIRKWOOD,  J.  P.  Report  on  the  Filtration  of  River  Waters  for  the  supply 

of  Cities,  as  practiced  in  Europe.  Ulus.  4to. 15  00 

“ Collection  of  Reports  and  Opinions  of  Chemists  in  regard 

to  the  use  of  Lead  Pipes  for  Service  Pipes  in  the  dis- 
tribution of  waters  for  the  supply  of  cities.  8vo. 1 50 

KREPP,  FRED.  CHAS.  The  Sewage  Question ; the  systems  and  methods 
hitherto  employed  in  various  countries  for  draining  cities  and  utilizing 

sewage,  with  a description  of  Liernur’s  System,  &c.  8vo  5 CO 

LATHAM,  B.  Sanitary  Engineering  ; the  Construction  of  Works  of  Sewer- 
age and  House  Drainage.  Second  edition  enlarged.  8vo.  Ulus 12  00 


W.  & L.  E.  GURLEY’S  LIST  OF  BOOKS. 


313 


Price 


LEFFEL.  The  Construction  of  Mill  Dams.  16mo $ 50 

PHILBRICK,  E.  S.  American  Sanitary  Engineering.  8vo.  1880  edition  . . 2 00 

STEVENSON,  D.  Canal  and  River  Engineering.  Illustrated.  8vo 6 00 

“ THOS.  The  Design  and  Construction  of  Harbors.  8vo 6 00 

STEWART,  H.  Irrigation  for  the  Farm,  Garden,  and  Orchard  Illustrated. 

New  York 1 50 

SWINDELL,  J.  G.  Well  Sinking,  Boring,  and  Pump-work.  (Weale’s 

series.) 80 

TREDGOLD,  THOS.  Tracts  on  Hydraulics,  containing  Smeaton’s  experi- 
mental papers  on  the  power  of  water  to  turn  mills,  &c.  Plates.  8vo  ...  2 50 

WARING,  G.  E.  Sanitary  Drainage  of  Houses  and  Towns.  12mo 2 00 

“ Draining  for  Profit  and  Health.  How  to  lay  out  a system 

of  drains  and  how  to  construct  the  drains.  Illustrated. 

12mo 1 50 

WEISBACH,  J.  Hydraulics  and  Hydraulic  Motors.  380  engravings.  8vo...  5 00 


MACHINERY  AND  MECHANICS. 


ABEL,  C.  D.  Machinery  Construction.  Plates.  (Weale’s  series.) $3  30 

APPLETON’S  Dictionary  of  Mechanics.  2 vols 15  00 

ARMSTRONG,  R.  Steam  Boilers.  (Weale’s  series.) 60 

BAKER,  T.  Mechanism,  Tools,  and  Machinery.  (Weale’s  series.) 1 00 

“ Steam  Engine.  (Weale’s  series.) 60 

BOURNE,  JOHN.  A Catechism  of  the  Steam  Engine.  New  edition.  12mo.  2 00 
“ Hand-book  of  the  Steam  Engine.  Constituting  a key  to 

the  “ Catechism  of  the  Steam  Engine.”  Illustrated 

with  67  woodcuts.  12mo 1 75 

BYRNE,  OLIVER.  Hand-book  for  the  Artisan,  Mechanic  and  Engineer. 

Illustrated  by  185  wood  engravings.  8vo 5 00 

CLARK,  D.  K.  A Manual  of  Rules,  Tables,  and  Data  for  Mechanical  Engi- 
neers based  on  the  most  recent  investigations.  Illustrated  with  numer- 
ous diagrams.  Large  octavo 7 50 

COOPER,  J.  II.  Use  of  Belting  for  Transmission  of  Power.  8vo.  Illus 3 50 

FORNEY,  M.  N.  Catechism  of  Locomotives.  Theoretical  and  Practical 

Management.  Illustrated.  12mo 2 50 

GLYNN,  J.  Cranes  and  Machinery  for  Heavy  Bodies.  (Weale’s  series.).  ...  60 

GOODEVE.  T.  M.  Text-book  on  the  Steam  Engine.  12mo.  Illustrated 2 00 

HUGHES,  WM.  C.  American  Miller  and  Millwright’s  Assistant.  12mo  ....  1 50 

ISHERWOOD.  B.  F.  Engineering  Precedents  for  Steam  Machinery.  Ar- 
ranged in  the  most  practical  and  useful  manner  for  Engineers.  With 
illustrations.  8vo 2 50 


314 


W.  & L.  E.  GURLEY’S  LIST  OE  BOOKS. 


Price 

NYSTROM,  J.  W.  Elements  of  Mechanics.  8vo $2  50 

OVERMAN,  F.  Mechanics,  for  the  Millwright,  Machinist,  Civil  Engineer, 

and  Architect.  1881,  12mo 1 50 

PALLETTE,  H.  The  Miller,  Millwright,  and  Engineer’s  Guide.  12mo 3 00 

RANKINE,  W.  J.  M.  Manual  of  Machinery  and  Millworks.  4th  ed.,  Svo 5 00 

ROPER,  S.  Construction  and  Management  of  Steam  Engine  Boilers 2 00 

“ Hand-book  of  the  Locomotive  Engine.  l2mo,  6th  ed 2 50 

ROSE,  J.  The  Pattern  Makers  Assistant.  8vo 2 50 

SCHUMANN,  F.  A Manual  of  Heating  and  Ventilation.  Embracing  a 
series  of  Tables  and  Formulae  for  dimensions  of  heating,  flow  and  return 

pipes  for  steam  and  hot-water  boilers,  flues,  &c.  12mo.  Illustrated 1 50 

THOMAS,  J.  J.  Farm  Implements  and  Machinery.  12mo 1 50 

WEISBACH,  J.  Mechanics  of  Engineering.  Translated  from  the  Fourth 

German  edition.  Theoretical  Mechanics.  1882,  8vo 10  00 

WOOD,  DE  VOLSON.  Elements  of  Analytical  Mechanics.  8vo 3 00 

MATHEMATICS. 

BEATON,  A.  C.  Quantities  and  Measurements.  How  to  Calculate  and  Take 

them.  (Weale’s  series.) $ 60 

BRUHNS,  DR.  Manual  of  Logarithms,  seven  places  of  Decimals.  8vo 2 50 

CHAUVENET,  W.  Treatise  on  Elementary  Geometry.  8vo 1 75 

“ Trigonometry 1 75 

CHURCH,  A,  E.  Elements  of  Calculus.  8vo 2 25 

“ Analytical  Geometry.  8vo 2 25 

CRAIG,  B.  F.  The  Decimal  System.  16mo 50 

DAVIES,  C.  Mathematical  Dictionary.  8vo 5 00 

“ Practical  Mathematics  and  Mensuration 1 50 

“ Mathematical  Tables. 1 00 

“ Metric  System 1 50 

GREGORY,  O.  Mathematics  for  Practical  Men.  Svo 5 00 

ROBINSON’S  Geometry  and  Trigonometry.  8vo 2 25 

WARREN,  S.  E.  New  Descriptive  Geometry.  8vo 3 50 

POCKET-BOOKS,  TABLES,  &c. 

BASHFORTH,  F.  Earthwork  Tables.  8vo $1  50 

BOILLEAU,  J.  T.  Complete  Set  of  Traverse  Tables,  showing  the  difference 

of  latitudes  and  the  departures  to  every  minute  of  the  quadrant.  8vo — 5 00 


W.  & L.  E.  GURLEY'S  LIST  OE  BOOKS. 


315 


Price 

BOWDITCH,  N.  Useful  Tables  from  Bowditch’s  Practical  Navigator.  8vo.  $1  25 
BURT,  W.  A.  Key  to  the  Solar  Compass,  and  Surveyor’s  Companion.  Com- 
prising all  the  rules  necessary  for  use  in  the  field ; also  description  of 
the  Linear  Surveys  and  Public  Land  System  of  the  United  States,  Notes 
on  the  Barometer,  suggestions  for  an  outfit  for  a survey  of  four  months, 

etc 2 50 

BYRNE,  O.  Pocket-Book  for  Railroad  and  Civil  Engineers 1 75 

CLEVENGER,  S.  V.  A Treatise  on  the  method  of  Government  Surveying. 

With  complete  Mathematical,  Astronomical  and  Practical  Instructions, 

for  the  use  of  United  States  Surveyors 2 50 

GRISWOLD,  W.  Pocket  Companion  for  the  Field 1 75 

HAMILTON,  W.  G.  Useful  Information  for  Railway  Men.  8th  edition 2 00 

HASWELL,  C.  H.  Engineer’s  and  Mechanic’s  Pocket-Book.  8th  edition ...  3 00 

HENCK,  J.  B.  Engineer’s  Field-Book.  Containing  formulae  for  laying  out 
Curves,  determining  Frog  Angles,  Leveling,  calculating  Earthworks,  &c. ; 

also  numerous  tables.  New  York,  1881  2 50 

LAW,  H.  Tables  of  Logarithms  ; with  Tables  of  Natural  Sines,  &c 1 40 

MOLES  WORTH,  G.  L.  Pocket-Book  of  Formulae  for  Engineers.  Revised..  2 00 

MORRIS,  E.  Easy  Rules  for  Measurement  of  Earthworks.  8vo 150 

NYSTROM,  J.  W.  Pocket-Book  of  Mechanics  and  Engineering.  Revised...  3 50 
RANKINE,  W.  J.  M.  Useful  Rules  and  Tables  for  Builders,  Engineers,  and 

Mechanics.  New  edition,  1883 4 00 

SCHUMANN,  F.  Formulas  and  Tables  for  Architects  and  Engineers  in  cal- 
culating the  strains  and  capacity  of  structures  in  Iron  and  Wood.  12mo.  2 50 

SCRIBNER,  J.  M.  Engineers’,  Contractors’,  and  Surveyors’  Pocket  Table- 
Book.  Comprising  Logarithms  of  Numbers,  Loga- 
rithmic Sines  and  Tangents,  Natural  Sines  and  Natural 
Tangents,  the  Traverse  Table,  and  a full  and  complete 
set  of  Excavation  and  Embankment  Tables.  16mo. . . 1 50 
Engineers’  and  Mechanics’  Companion.  19th  edition. . . 1 50 
SEARLES,  WM.  H.  Field  Engineering.  A Hand-Book  of  the  Theory  and 
Practice  of  Railway  Surveying,  Location  and  Con- 
struction, and  containing  a large  number  of  Useful 

Tables.  Third  edition.  1882 . 3 00 

The  Railroad  Spiral.  The  Theory  of  the  Compound 
Transition  Curve  reduced  to  Practical  Formulse  and 

Rules  for  Application  in  Field  Work 1 50 

SHUNK,  W.  F.  The  Field  Engineer.  A handy  book  of  practice  in  the  Sur- 
vey, Location,  and  Track-work  of  Railroads,  containing  a 
large  collection  of  Rules  and  Tables  applicable  to  both  the 

Standard  and  Narrow  Gauge.  Fourth  edition 2 50 

Treatise  on  Railway  Curves 2 00 

TABLES  AND  FORMULAE  useful  in  Surveying,  Geodesy  and  Practical  As- 
tronomy, being  No.  12  Professional  Papers  of  the  corps  of  Engineers  of 

the  U.  S.  Army 5 00 

TEMPLETON,  W.  Millwright’s  and  Engineer’s  Companion 2 00 

TRAUTWINE,  J.  C.  Excavations  and  Embankments 2 00 

Railroad  Curves.  New  edition,  1882 2 50 


316  w.  & l.  e.  gurley’s  list  of  books. 

Price 

TRAUTWINE,  J.  C.  Civil  Engineer’s  Pocket-Book  of  Mensuration,  Trigo- 
nometry, Surveying,  Hydraulics,  Hydrostatics,  Strength  of  Materials, 
Masonry,  Principles  of  Wooden  and  Iron  Roof  and  Bridge  Trusses,  Stone 
Bridges  and  Culverts,  Trestles,  Pillars,  Suspension  Bridges,  Dams,  Rail- 
roads, Turnouts,  Turning  Platforms,  Water  Stations,  Cost  of  Earthwork, 

Foundations,  Retaining  Walls,  &c $5 

VEGA,  BARON  VON.  Logarithmic  Tables.  8vo 2 

SURVEYING  AND  ENGINEERING. 

See  also  Pocket- Books , Tables , <&c. 

BAKER,  T.  Land  and  Engineering  Surveying.  (Weale’s  series.) $ 80 

“ Railway  Engineering ; containing  approved  methods  of  Laying 
Out  Railway  Curves,  and  of  Setting  Out  the  Widths  of  the 
Cuttings  and  Embankments,  a General  Table  for  the  Calcula- 
tion of  Earthworks,  etc.,  also  Tunneling,  and  Investigation 
of  the  Formula  for  the  Superelevation  of  the  Exterior  Rail  in 

Curves.  8vo.  Illustrated 2 50 

BALCH,  G.  T.  General  Classification  of  Railway  Rights,  Realties  and  Per- 
sonalties, &c.  In  one  volume  folio,  200  pages 5 00 

CLEEMANN,  T.  M.  The  Railroad  Engineers’  Practice.  12mo.  1883 1 50 

DAVIES,  CHAS.  Elements  of  Surveying  and  Levelling ; with  treatises  on 

Topography,  Railway  Curves,  and  Mining  Surveying.  Revised,  1883.  12mo.  2 50 

FENWICK,  T.  Subterraneous  Surveying.  (Weale’s  series.) 100 

FROME,  COL.  Method  of  Conducting  a Trigonometrical  Survey,  for  the 

Formation  of  Geographical  and  Topographical  Maps.  8vo 6 00 

GILLESPIE,  W.  M.  Practical  Treatise  on  Surveying.  8th  ed.,  1883.  8vo. ..  2 50 
“ Higher  Surveying.  A Treatise  on  Leveling,  Topog- 
raphy, Mining  Surveying,  &c.  8vo 2 50 

“ Principles  and  Practice  of  Road-Making.  12mo.  Tenth 

edition 2 50 

GILLMORE,  GEN.  Q,.  A.  Practical  Treatise  on  the  Construction  of  Roads, 

Streets,  and  Pavements.  With  70  illustrations.  12mo 2 00 

HAUPT,  L.  M.  A Manual  of  Engineering  Specifications  and  Contracts,  de- 
signed as  a Text-book  and  Work  of  Reference  for  all  who 
may  be  engaged  in  the  Theory  or  Practice  of  Engineering. 

8vo.  Illus 3 00 

“ The  Topographer ; his  Instruments  and  Methods.  Fully 

illustrated.  8vo.  1884 4 00 

HAWES,  J.  H.  System  of  Rectangular  Surveying  ; being  a Manual  of  U.  S. 

Government  Surveying.  8vo 3 00 

JEFFERS,  W.  N.  Treatise  on  Nautical  Surveying.  8vo.  Illustrated 5 00 

LAW  & BURNELL’S  Civil  Engineering.  (Weale’s  series.) 2 60 


g g 


W.  & L.  E.  GURLEY’S  LIST  OF  BOOKS. 


317 


Price 


MAHAN,  D.  H.  A Treatise  on  Civil  Engineering.  8vo.  Revised  by  De  Vol- 

son  Wood.  New  edition,  1880 $5  00 

MURRAY,  D.  Manual  of  Land  Surveying  ; with  Tables  of  Logarithms,  Sines 
and  Tangents,  Natural  Tangents  and  Cotangents,  and  Traverse  Table. 

12mo 2 00 

PLANE  TABLE,  and  its  use  in  Topographical  Surveying.  From  the  papers 

ofU.  S.  Coast  Survey.  Illustrated.  8vo * 2 00 

RANKINE,  W.  J.  M.  Civil  Engineering,  comprising  Engineering  Surveys, 
Earthwork,  Foundations,  Masonry,  Carpentry,  Metal  works,  Roads,  Rail- 
ways, Canals,  Rivers,  Water-works,  Harbors,  &c.,  with  numerous  tables 

and  illustrations.  14th  edition.  8vo.  London,  1883 6 50 

ROBINSON’S  Surveying  and  Navigation.  With  use  of  instruments,  essen- 
tial Elements  of  Trigonometry,  Mensuration,  and  the  necessary  Tables. 

Edited  by  Oren  Root,  A.  M.,  of  Hamilton  College.  8vo 2 25 

SIMMS,  F.  W.  A Treatise  on  the  Principles  and  Practice  of  Leveling.  Fifth 
edition,  revised.  With  Law’s  method  of  laying  out  Curves. 

8vo.  New  York 2 50 

“ Practical  Tunnelling.  Third  edition,  revised.  8vo 7 50 

STEVENSON,  D.  Civil  Engineering  of  North  America.  (Weale’s  series.). . 120 

STONE,  J.  B.  Magnetic  Variation  in  the  United  States.  12mo 1 50 

VAN  NOSTRAND’S  Engineering  Magazine.  Per  No.,  50  cents  ; yearly 5 00 

VOSE,  GEO.  L.  Hand-book  of  Railroad  Construction,  with  plans,  maps,  &c. 

The  most  complete  hand-book  of  railway  construction  yet  published 12  50 

WELLINGTON,  A.  M.  The  Ecouomic  Theory  of  the  Location  of  Railways. 
(Reprinting.) 

“ Railway  Earthworks,  with  Diagrams.  2 vols.  Illus- 
trated   5 00 


TREATISES  ON  INSTRUMENTS,  &c. 


BREWSTER,  SIR  DAVID.  Treatise  on  Optics.  12mo $1  40 

GURLEY,  W.  & L.  E.  Manual  of  the  Principal  Instruments  used  in  Ameri- 
can Engineering  and  Surveying.  25th  edition,  1884 50 

HEATHER’S  Treatise  on  Mathematical  Instruments.  (Weale’s  series.) 60 

“ Treatise  on  Optical  Instruments.  (Weale’s  series.) 60 

Treatise  on  Surveying  and  Astronomical  Instruments.  (Weale’s 

series.) 60 

HOGG,  J.  The  Microscope  ; its  History,  Construction,  and  Application.  8vo.  3 50 
HO  ARE,  C.  The  Slide  Rule,  and  How  to  Use  it ; containing  full,  easy,  and 
simple  instructions  to  perform  all  business  calculations  with  unexampled 

rapidity  and  accuracy.  With  a slide  rule  in  tuck  of  cover 1 00 

HULME,  F.  E.  Mathematical  Drawing  Instruments,  and  how  to  use  them. 

Illustrated.  12mo 1 50 

LANKESTER,  EDWIN.  Half  Hours  with  the  Microscope.  16mo 2 00 

NUGENT.  E.  Treatise  on  Optics.  12mo.  103  illustrations 1 50 

PLYMPTON,  G.  W.  System  of  Instruction  in  the  Practical  use  of  the  Blow- 
pipe. 12mo.  Illustrated 1 50 


318  W.  & L.  E.  GURLEY'S  L1S1  OE  BOOKS. 

Price 

STANLEY,  W.  F.  A Descriptive  Treatise  on  Mathematical  Drawing  Instru- 
ments, their  construction,  uses,  qualities,  selection,  etc.;  with  hints  upon 

drawing  and  coloring.  12mo $2 

WARREN,  S.  E.  Drafting  Instruments  and  Operations.  12mo 1 

MISCELLANEOUS. 

ALEXANDER,  J.  H.  Weights  and  Measures,  Ancient  and  Modern,  reduced 

to  Standard  of  the  United  States  of  America.  8vo 3 

BENJAMIN,  PARK.  Engineers  and  Mechanics  Recipes.  Thirteenth  edition. 

12mo,  300  pp 2 

BOWDITCH,  N.  American  Practical  Navigator.  8vo 3 

CLARKE,  D.  K.  Fuel ; its  Combustion  and  Economy.  12mo 1 

DONALDSON,  J.  Clay  Lands  and  Loamy  Soils.  (Weale’s  series  ) 

GUETTIER.  Metallic  Alloys  : being  a Practical  Guide  to  their  Chemical  and 
Physical  Properties,  their  Preparation,  Composition,  and  Uses.  Translated 
from  the  French  of  A.  Guettier,  Engineer  and  Director  of  Foundries. 

12mo 3 

KEMP,  EDWARD,  on  Landscape  Gardening.  12mo,  illustrated 2 

KNIGHT,  E.  H.  American  Mechanical  Dictionary;  a description  of  Tools, 
Instruments,  Machines,  and  Engineering,  &c.  3 vols.,  8vo,  illustrated. ..  24 

LARKIN,  J AS.  The  Practical  Brass  and  Iron  Founder’s  Guide.  12mo 2 

LIPPINCOTT’S  Pronouncing  Gazetteer  of  the  World.  4to,  sheep 10  00 

PEPPER,  J.  H.  Cyclopedic  Science  Simplified.  8vo 3 75 

“ The  Boy’s  Play-book  of  Science,  including  the  various  ma- 

nipulations and  arrangements  of  Chemical  and  Philosoph- 
ical Apparatus  required  for  the  successful  performance  of 
Scientific  Experiments.  New  edition,  illustrated  with  470 

illustrations.  12mo 2 00 

SPON,  E.  Workshop  Receipts.  8vo 2 00 

URE'S  Dictionary  of  Arts,  Manufactures,  and  Mines.  Revised,  4 vols 36  00 

WEBSTER’S  Unabridged  Dictionary.  4to.  Sheep 12  00 


ggggg  88 


VAN  NOSTRAND'S  SCIENCE  SERIES. 

1 8 mo,  Fancy  Boards,  50  Cents  Each. 


No. 

1. — Chimneys  for  Furnaces,  Fire  Places,  and  Steam  Boilers.  By  R.  Armstrong,  C.  E. 

2. — Steam  Boiler  Explosions.  By  Zerah  Colburn. 

3. — Practical  Designing  of  Retaining  Walls.  By  Arthur  Jacob,  C.  E.  Illustrated. 

4. — Proportion  of  Pins  Used  in  Bridges.  By  Chas.  E.  Bender,  C.  E.  Illustrated. 

5. — Ventilation  of  Buildings.  By  W.  F.  Butler.  Illustrated. 

6. — On  the  Designing  and  Construction  of  Storage  Reservoirs.  By  Arthur 

Jacob,  C.  E. 

7. — Surcharged  and  Different  Forms  of  Retaining  Walls.  By  Jas.  S.  Tate,  C.  E. 

Illustrated. 

8.  —A  Treatise  on  the  Compound  Engine.  By  John  Turnbull.  Illustrated. 

9. — Fuel.  By  C.  William  Siemens.  To  which  is  appended  the  value  of  Artificial 

Fuels  as  compared  with  Coal,  by  John  Wormold,  C.  E. 

10.  — Compound  Engines.  From  the  French  of  A.  Mallet.  Illustrated. 

11. — Theory  of  Arches.  By  Prof.  W.  Allan.  Illustrated. 

12. — A Practical  Theory  of  Voussoir  Arches.  By  Wm.  Cain,  C.  E.  Illustrated. 

13. — A Practical  Treatise  on  the  Gases  met  with  in  Coal  Mines.  By  the  late  J.  J. 

Atkinson. 

14. — Friction  of  Air  in  Mines.  By  J.  J.  Atkinson. 

15. — Skew  Arches.  By  Prof.  E.  Hyde,  C.  E.  Illustrated. 

16. — A Graphic  Method  of  Solving  Certain  Algebraic  Equations.  By  Prof.  Geo.  L. 

Vose.  Illustrated. 

17. — Water  and  Water  Supply.  By  Prof.  W.  H.  Corfield. 

18.  — Sewerage  and  Sewage  Utilization.  By  Prof.  W.  H.  Corfield. 

19. — Strength  of  Beams  under  Transverse  Loads.  By  Prof.  W.  H.  Allan.  Illust. 

20. — Bridge  and  Tunnel  Centers.  By  John  B.  McMaster,  C.  E.  Illustrated. 

21.  — Safety  Valves.  By  Richard  H.  Buel,  C.  E.  Illustrated. 

22. — High  Masonry  Dams.  By  John  B.  McMaster,  C.  E.  Illustrated. 

23. — The  Fatigue  of  .Metals  under  repeated  Strains,  with  various  Tables  of  Results 

of  Experiments.  From  the  German  of  Prof.  Ludwig  Spangenburgh,  with  a 
Preface  by  S.  H.  Shreve,  A.  M. 

24. — A Practical  Treatise  on  the  Teeth  of  Wheels,  with  the  Theory  and  Use  of 

Robinson’s  Odontograph.  By  S.  W.  Robinson,  Professor  of  Mechanical 
Eng.,  111.  Industrial  University. 

25. — On  the  Theory  and  Calculation  of  Continuous  Bridges.  By  Mansfield  Merri- 

man,  Ph.D. 

26. — Practical  Treatise  on  the  Properties  of  Continuous  Bridges.  By  Charles  Ben- 

der, C.  E. 

27. — On  Boiler  Incrustation  and  Corrosion.  By  F.  J.  Rowan. 

28. — Transmission  of  Power  by  Wire  Ropes.  By  Albert  W.  Stahl,  U.  S.  N.  Illust. 

29. — Steam  Injectors : Translated  from  the  French  of  M.  Leon  Pochet. 

30. — Terrestrial  Magnetism  and  the  Magnetism  of  Iron  Vessels.  By  Prof.  Fairman 

Rogers. 


320 


VAN  NOSTRAND’S  SCIENCE  SERIES. 


No. 

31.— The  Sanitary  Condition  of  Dwelling  Houses  in  Town  and  Country  By  Geo 
E.  Waring,  Jr.  J 


32 —Cable  Making  of  Suspension  Bridges,  as  Exemplified  in  the  East  River  Brido-e 
By  Wilhelm  Hildenbrand,  C.  E.  With  illustration.  ^ 

33. — Mechanics  of  Ventilations.  By  Geo.  W.  Rafter,  C.  E. 

34. — Foundations.  By  Prof.  Jules  Gaudard,  C.  E.  Translated  from  the  French  by 

L.  F.  Vernon  Harcourt,  M.  J.  C.  E. 

35. — The  Aneroid  Barometer  ; 

Plympton. 


Its  Construction  and  Use.  Compiled  by  Geo.  W. 


38. — Matter  and  Motion.  By  J.  Clerk  Maxwell,  M.  A. 

37. — Geographical  Surveying.  Its  Uses,  Methods,  and  Results.  By  Frank  De 

Yeaux  Carpenter,  C.  E. 

38. — Maximum  Stresses  in  Framed  Bridges.  By  Prof.  Wm.  Cain,  A.  M.,  C.E.  Illust. 

39. — A Hand-Book  of  the  Electro-Magnetic  Telegraph.  By  A.  E.  Loring.  Illust. 

40. — Transmission  of  Power  by  Compressed  Air.  By  Robert  Zahner,  M.  E.  Illust. 

41. — Strength  of  Materials.  By  William  Kent,  C.  E.  Illustrated. 

42. — Voussoir  Arches  Applied  to  Stone  Bridges,  Tunnels,  Culverts,  Groined  Arches 

and  Domes.  By  Prof.  Win.  Cain,  C.  E. 


43. — Wave  and  Vortex  Motion.  By  Dr.  Thomas  Craig,  of  Johns  Hopkins  University, 

44.  — 1 Turbine  Wheels.  By  Prof.  W.  P.  Trowbridge,  Columbia  College.  Illustrated. 

45.  — Thermodynamics.  By  Prof.  H.  T.  Eddy,  University  of  Cincinnati. 

46. — Ice-making  Machines.  From  the  French  of  M.  Le  Doux.  Illustrated. 

47. — Linkages ; the  Different  Forms  and  Uses  of  Articulated  Links.  By  J.  D.  C. 

De  Roos. 

48. — Theory  of  Solid  and  Braced  Arches.  By  Wm.  Cain,  C.  E. 

49. — On  the  Motion  of  a Solid  in  a Fluid.  By  Thomas  Craig,  Ph.  D. 

50. — Dwelling  Houses:  their  Sanitary  Construction  and  Arrangements.  By  Prof. 

W.  H.  Corfield. 

51. — The  Telescope:  its  Construction,  &c.  By  Thomas  Nolan. 

52. — Imaginary  Quantities  : Translated  from  the  French  of  M.  Argand.  By  Prof. 

Hardy. 

53. — Induction  Coils  : How  Made  and  How  Used. 

54.  — Kinematics  of  Machinery.  By  Prof.  Kennedy.  With  an  Introduction  by  Prof. 

R.  H.  Thurston. 

55. — Sewer  Gases  : their  Nature  and  Origin.  By  A.  De  Varona. 

56.  — The  Actual  Lateral  Pressure  of  Earthwork.  By  Benj.  Baker,  M.  Inst.  C.  E. 

57. — Incandescent  Electric  Lights,  with  Particular  Reference  to  the  Edison  Lamps 

at  the  Paris  Exhibition.  By  Compte  Th.  Du  Moncel  and  Wm.  Henry  Preece. 
Second  edition  revised. 

58. — The  Ventilation  of  Coal  Mines.  By  W.  Fairley,  M.  E. 

59.  — Railroad  Economics.  By  S.  W.  Robinson,  C.  E. 

60. — Strength  of  Wrought  Iron  Bridge  Members.  By  S W.  Robinson,  C.  E. 

61. — Potable  Water  : ana  Methods  of  Detecting  Impurities.  By  Chas.  W.  Folkard. 

62. — The  Theory  of  the  Gas  Engine.  By  Dugald  Clerk. 

63. — House  Drainage  and  Sanitary  Plumbing.  By  W.  P.  Gerhard. 

64. — Electro-Magnets.  By  Th.  Dumoncel. 

65. — Pocket  Logarithms  to  Four  Places  of  Decimals. 

66. — Dynamo -Electric  Machinery.  By  S.  P.  Thompson. 

67. — Hydraulic  Tables.  By  P.  J.  Flynn. 

68.  — Steam  Heating.  By  R.  Briggs. 

69. — Chemical  Problems.  By  J.  C.  Foye 

70. — Explosives.  By  M.  Bertholet. 

71. — Dynamic  Electricity.  By  John  Hopkinson,  J.  A.  Schoolbred,  and  R.  E.  Day. 

For  Sale  by 

W.  & L.  E.  GURLEY, 


TROY,  N.  Y. 


TABLE  OF  CONTENTS 


PAGE 

Abney  Level  and  Clinometer 10,  198 

Adjustment  of  Engineers’  and  Surveyors’  Transits • 39-46,  77,  80-82 

Do.  * Vernier  Transit  Compass 87 

Do.  Solar  Attachment 

Do.  Solar  Compass 100-103,  150 

Do.  Surveyors’  Compasses 122,  133,  139 

Do.  Engineers’  Y Levels 169-175 

Do.  Architects’  Level 1?8 

Do.  Drainage  Level 182 

Do.  Telescopic  Sight 141-145 

Do.  Line  of  Collimation .40-44.  171,  172 

Do.  Object-slide ••33,  46,  169,  170 

Alidades  for  Plane-Tables .7,  192, 194-196 

Alt- Azimuth 

Alteneder’s  Patent  Joint  Drawing  Instruments 231,  232 

Aneroid  Barometers 15,  16 

Architects’  Ivory  Scales • • • • — 249,  250 

Do.  Boxwood  Scales 251 

Do.  Level 7,177-181 

Do.  Rod 10,188,  189 

Astronomical  Terms 92-98 

Do.  Telescopes 277 

Attachments  of  Telescope 6,  8,  34,  50,  52,  76,  167 

Barometers,  Aneroid 15, 16 

Ball  Spindle 17, 126 

Batter  Slopes 260 

Blow-pipes 301 

Blue  Process  of  copying  tracings 280 

Bond  Paper  279 

Books 286-288,  303-320 

Boston  Rod 10,  184,  185 

Boxes  for  Colors 292,  293 

Boxwood  Scales 250-253 


322  TABLE  OF  CONTENTS. 

PAGE 

Brass  Scales  and  Rules 252,  267,  268 

Bronze  Finish 22,  207,  208 

Brass  Drawing  Instruments 233-235 

Brushes 295-297 

Center  Pin 136, 137 

Chains,  American 11,  209-213 

Do.  Spanish  or  Mexican  Vara 11,  212 

Do.  Grumman’s  Patent 12,  211 

Do.  French  or  Metre 11,  212 

Chain  Scale,  Ivory 249 

Do.  Boxwood 251,252 

Clamp  and  Tangent  6,  36,  76,  77 

Clinometer 10,  198 

Colors,  Winsor  & Newton’s 290-292 

Compasses,  Railroad 8,  9,  119-125 

Do.  Vernier  8,9,  126-138 

Do.  Plain.... 8,139-146 

Do.  Solar 7,9,  88-118, 147-150 

Do.  Pocket 9,  147-161,  269,  270 

Do.  Dial 9,160,161 

Do.  Miners’,  or  Dipping  10, 157, 158 

Do.  Extras  to 8,9 

Compound  Ball, 8,86,87 

Cross  Wire  and  Ring 23,  24,  30,  31,  33 

Cross  Section  Paper 283-285 

Crozet’s  Protractor 246 

Curves,  Horn,  Wood,  and  Rubber 226,  227,  262-265 

Declination  Arc . 53,  57,  90 

Detachable  Telescope  . 6,  67,  68 

Diagonal  Prism  for  Eye-piece 6,  29,  66 

Dial  Compass 9,  160,  161 

Dip  Compasses 10,  157, 158 

Diurnal  Variation 120 

Drainage  or  Farmers’  Level 7, 181, 182 

Drawing  Instruments,  Swiss 224-231,  243,  244 

Do.  Alteneder’s  Patent  Joint 231,232 

Do.  Brass 233-235 

Do.  German  Silver 236-242 

Drawing  Paper 278-285 

Do.  Boards 399 

Do.  Tables * 300 

English  or  Telescopic  Rod ^ 190 

Equation  of  Time 96 

Erasing  Knives • 


TABLE  OF  CONTENTS. 


323 


PAGE 

Excavation  and  Embankment  Tables 288 

Extension  Tripod 6,  9,  39,  69,  204 

Eye-piece,  how  composed 28-30 

Do.  Kellner.  30 


Farmers’  or  Drainage  Level 7,  181,  182 

Field  Glasses  for  Tourists 274-277 

Field  Note  Books 286,  287 

Finish  of  Instruments * 22 

Flag  Staff  or  Ranging  Pole 10 


German  Silver  Drawing  Instruments 236-242 

General  Matters 203-214 

Gradienter 6,70-72 

Graduations  of  Limb  to  10,  20,  or  30  seconds 6 

Grumman' s Patent  Chain 12,  211 

Hand  Level,  Locke’s 10, 197 

High  Power  Telescopes 30 

Hydrometers 301 

Hyperbolas 261 

Information  to  Purchasers  . . 19-24 

India  Ink 292-294 

Ink  Slabs  and  Saucers 289 

Ink,  Writing,  or  Carmine 300 

Inverting  Eye-piece 29 

Ivory  Scales  and  Rules 248-250,  267 


Jacob  Staff  Mountings 17,  126 

Jones’  Patent  Latitude  Arc 6,  60-63 

Kellner  Eye-piece 30 

Lacquering 207,  208 

Lamp,  Plummet 6,  68 

Latitude  Arc 53,  54,  59-63,  90 

Leather  Cases 9,  72 

Leveling  Adopter 8,  9,  104,  202 

Leveling  Instruments 6.  7,  162-182, 197,  198 

Do.  Instruments,  Y Levels 6,  7, 162-181 

Do.  Instruments,  Architects 7,  177-181 

Do.  Instruments,  Farmers’  or  Drainage 7, 181, 182 

Do.  Rods 10,183-190 

Do.  Tripod-head,  quick 7,  205-207 

Level  on  Telescope 6,  80-82 

Limb  Protractors  247 


324 


TABLE  OE  CONTENTS, 


PAGE 

Local  Attraction 120 

Locke’s  Hand  Level . 10, 197 

Lyons’ Tables 288 

Machinists’  Tools,  etc 301 

Marking  Iron,  or  Timber  Scribe 12 

Marking  Pins 12,  212 

Magnifying  Power  of  Telescope . , 29 

Magnetic  Needle 35,  36,  119,  120,  124,  133, 136 

Magnets 269 

Marine  Glasses 274,  275 

Metallic  Scales 252,  253 

Metallic  Tapes 12,  214 

Metric  Paper  (Profile  and  Cross  Section) 283,  285 

Do.  Rods 10,189 

Do.  Rules  and  Scales 252-254 

Do.  Chains  12,  212 

Micrometer  Telescope 8, 113,  114 

Micrometer  or  Stadia  Wires . 33 

Microscopes 272,  273 

Miners’  Dip  Compasses 10,  158,  159 

Miscellaneous 17.300,  301,  318 

Needle,  Magnetic 35,  36, 119,  120,  124,  1&3,  136 

New  York  Rod 10, 185,  186,  188 

Object  Glass  of  Telescopes . . 28 

Odometer 14, 199-202 

Oil  Stones 301 

Opera  Glasses 275 

Optical  Axis 32 

Do.  Principles  of  the  Telescope 29,  32 

Outkeeper 17,  129 

Ovals 261 

Packing,  etc 21 

Pantographs 266 

Paper,  Drawing,  Tracing,  Sensitive,  etc 278-285 

Parabolas 261 

Parallel  Rules 265,  266 

Parts  of  Instruments  liable  to  injury,  prices  of € 16, 17 

Patent  Extension  Tripod 6,  9,  39,  69,  204 

Payment,  Terms  of 22 

Pedometer 271 

Pens,  Mapping  and  Writing 297 

Pencils  298 

Philadelphia  Rod 10, 183,  184 


TABLE  OF  CONTENTS. 


325 


PAGE 

Pinion  *to  Eye-piece 6, 166 

Plane  Tables 7,  191-196 

Platinum  Cross- wires.  23,  24.  30,  31 

Plumb-bobs 12, 14, 17 

Plummet  Lamp 6,  68 

Pocket  Compasses 9,  147-161,  269,  270 

Do.  Alt- Azimuth 270 

Do.  Rules 267,  268 

Power  of  Telescopes 29,  30 

Protractors,  Brass  and  German  Silver 243-246 

Do.  Horn,  Rubber,  and  Paper 245,  246 

Do.  Ivory  and  Boxwood 248-250 

Do.  Crozet’s 246 

Do.  New  Limb 247 

Profile  Paper 282,  283 

Do.  Books „ 286,  287 

Prismatic  Compass 270 

Prisms,  Diagonal,  for  Eye-piece 6,  29,  66 

Price  List 5-17,  224-320 


Quick-leveling  Tripod-bead. 


7,  205-207 


Rack  and  Pinion 

Ranging  Poles 

Railroad  Compass 

Do.  Pocket  Compass 

Rain  Gauge 

Repairs  to  Instruments 

Do.  Compasses 

Do.  Transits  and  Levels 

Reading  Glasses 

Reflector  for  Object-glass 

Refractions,  Table  of 

Right  Angle  Sights 

Rod  Level 

Rods,  Leveling 

Rules 

Rubber  Goods 


6,  166 

10 

8, 119-125 

9, 151-154 

301 

22, 23 

23,  136-138 

23,  24 

273 

6,  66 

106-108,117,  118 

6 

10 

10,  183-190 

251,  253-255,  265-268 

245,  257-261,  263-266,  272,  273,  298-300 


Scales,  Metal,  Wood,  Ivory,  etc 248-250,  253 

Scales,  Paper 253 

Sector  Scales,  Ivory,  etc 249 

Section  Liners \ 266 

Selection  of  Instruments 19 

Sensitive  Paper 280,  281 

Sextant 271 

Shifting  Plate  or  Head 39 


326 


TABLE  OF  CONTENTS. 


Sights  on  Telescope 

Do.  at  right  angles ...  

Size  of  Engineers’  Transits 

Do.  Surveyors’  Transits 

Do.  Vernier  Transits 

Do.  Y Levels 

Do.  Architects’  Level 

Do.  Railroad  Compasses 

Do.  Vernier  Compasses 

Do.  Plain  Compasses 

Sketching  Blocks  and  Pads.  

Slabs  and  Saucers 

Smaller  Instruments 

Sockets  of  Transits 

Do.  Levels 

Solar  Apparatus,  Explanation  of 

Solar  Attachment  to  Transits 

Solar  Compasses 

Special  Notices 

Spirit  Levels 

Spring  Balance 

Squares,  German  Silver 

Square  Steel  Rules 

Standard  Steel  Ribbons 

Straight  Edges,  Steel,  Rubber,  and  Wood 

Steel  Goods 

Steel  Tapes 

Surveyors’  Cross  

Stadia.  — . 

Swiss  Drawing  Instruments 


Tables,  Drawing 300 

Do.  Excavation  and  Embankment 288 

Do.  Plane 7,191-196 

Do.  Refraction 106-108,  117,  118 

Do.  Traverse  215-221 

Tacks 267 

Tapes,  Chesterman’s  Metallic ...  12,  214 

Do.  do.  do.  Without  Box 12 

Do.  do.  Steel 13,214 

Do.  do.  do.  Pocket 13 

Do.  Paine’s  Patent  Steel . 13,  214 

Do.  Extras  to #... 13 

Tangent  Scale  — 128 

Telemeter  Rods 10,  189 

Telescopes  and  Tourists’  Glasses 276,  277 

Do.  for  vertical  sighting 6,  9,  67,  68 


page 

6 

6 

50 

82 

88 

176 

177 

125,  152 

138,  154 

146,  157,  159 

281 

289 

9,  10,  197-202 

34,  38,  39,  74,  75,  79 

165,  168 

54-56 

5,  6,  48,  49,  52-66,  83,  84 
....7,  9,  88-118,  147-150 

18,223 

16,  17,  128,  270,  301 

12,  13 

256 

255 

14,  214 

255,  257 

....254-256,  261,  297,  299 

13,214 

271 

. 33 

224-231,  243,  244 


TABLE  OF  CONTENTS. 


327 


Telescope,  how  composed 

Do.  high  power 

Telescopic  Rod 

Do.  Sight 

Thermometers 

Theodolite  Axis 

Timber  Scribe,  or  Marking  Iron 

Township  Plotting  Paper 

Trammel  Points 

Tracing  Paper 

Do.  Cloth,  or  Vellum 

Transits,  Vernier 

Do.  Surveyors1  One  Vernier.  .. 

Do.  do.  Two  do 

Do.  Engineers’  Two  do 

Do.  Theodolite  Axis 

Do.  Light  Mountain 

Do.  Extras  to 

Do.  Patent  Solar  Attachment  to 

Do.  Solar  

Transportation  of  goods 

Traverse  Tables 

Trial  of  Instruments 

Trangular  Boxwood  Scales 

Do  Metalic  Scales 

Do.  Steel  Rules.  

Triangles,  Steel  and  German  Silver. . . 

Do.  Rubber 

Do.  Wood  

Tripods 

Do.  Extension... 

Tripod  Head,  Quick-leveling 

T Squares,  Wood.  Rubber,  and  Steel. . 
Troy  Rod 


PAGE 

28,  29,  162-166 

30 

10,190 

8,  113,  114, 139-146 

13,301 

5, 50 

12 

281 

268,  269 

279 

280 

6,  85-88 

5,  6,  78-84 

5,  73-77 

5,  27-50 

5,  50 

5,  51-72 

6 

5,  6,  52-66 

5,  6,  48,  49,  51-66,  83,  84 

21 

215-221 

20 

252,  253 

252 

255 

. 256 

257-259 

, 259,  260 

..6.8,  9,69,203-207,277 

6,  9,  39,  69,  204 

7,  205-207 

260,  261 

10,  187 


Vara  Chains 11.  212 

Variation  of  Needle 19,  120,  124,  130-132 

Do.  to  turn  off. 131 

Verniers 37, 130 

Vernier  Compasses 8,  9, 126-138 

Do.  Pocket  Compass 9, 154-157 

Do.  to  read  the 130 

Vertical  Circle 6,  76,  77 

Do.  Arc,  with  movable  Vernier 6,  53,  54 

Vellum 280 


Warranty . 


20 


328 


TABLE  OF  CONTENTS. 


PAGE 

Water  Colors,  Winsor  & Newton’s  290-292 

Do.  Box 292,  293 

Weights  of  Plain  Compasses 146 

Do.  Vernier  Compasses 138 

Do.  Vernier  Transits 88 

Do.  Surveyors’  Transits 82 

Do.  Solar  Compasses 116,150 

Do.  Railroad  Compasses 125 

Do.  Light  Mountain  Transit 72 

Do.  Engineers’  Transits 50 

Do.  Y Levels 176 

Do.  Patent  Soiar  Attachment 65 

Do.  Attachments  to  Transits 82 

Y Levels 6,  7,  162-181 


Zimmerman’s  Tables 


THE  RENSSELAER  POLYTECHNIC  INSTITUTE, 

TROY,  N.  Y. 

FOUNDED  1 1ST  1824. 


BOARD  OF  TRUSTEES. 


Hon.  JAMES  FORSYTH,  President. 
WILLIAM  GURLEY,  Vice-President. 
WILLIAM  H.  DOUGHTY,  Secretary. 
WILLIAM  H.  YOUNG.  Treasurer. 


JOSEPH  M.  WARREN. 

E.  THOMPSON  GALE. 
LYMAN  WILDER. 

URI  GILBERT. 

CHARLES  R.  INGALLS. 
WILLIAM  A.  SHEPARD. 
Rev.  WILLIAM  IRVIN,  D.  D. 
CHARLES  MACDONALD. 
ELIAS  P.  MANN. 


ALBERT  E.  POWEES. 

DAVID  COWEE. 

JAMES  S.  KNOWLSON. 

JOSEPH  W.  FULLER. 

WILLIAM  KEMP. 

Rev.  J.  IRELAND  TUCKER.  D.D. 
HENRY  C.  LOCKWOOD. 

JAMES  P.  WALLACE. 

JOSEPH  C.  PLATT,  Jr. 


Hon.  EDMUND  FITZGERALD,  Mayor  of  Troy , Ex-Officio . 


FACULTY  AND  INSTRUCTORS. 

Hon.  JAMES  FORSYTH,  LL.  D.,  President. 

Lecturer  on  the  Law  of  Contracts. 

DAVID  M.  GREENE,  C.  E.,  Director. 

Professor  of  Geodesy , Road  Engineerings  and  Topographical  Drawing. 
CHARLES  DROWNE,  C.  E.,  A.  M. 

Emeritus  Professor  of  Theoretical  and  Practical  Mechanics. 

JAMES  HALL,  LL.  D.,  N.  Y.  State  Geologist. 

Emeritus  Professor  of  Theoretical , Practical , and  Mining  Geology. 
DASCOM  GREENE,  C.  E. 

Professor  of  Mathematics  and  Astronomy. 

HENRY  B.  NASON,  Ph.  D.,  M.  D.,  LL.  D. 

Professor  of  Chemistry  and  Natural  Science. 

DWINEL  FRENCH  THOMPSON,  B.  S. 

Professor  of  Descriptive  Geometry , Stereotomy , and  Drawing. 
WILLIAM  HUBERT  BURR,  C.  E. 

William  Howard  Hart  Professor  of  Rational  and  Technical  Mechanics. 
RICHARD  HALSTED  WARD,  A.  M.,  M.  D 
Professor  of  Botany. 

FRANK  PERKINS  WHITMAN,  A.  M. 

Professor  of  Physics. 

JULES  GODEBY,  A.  B. 

Instructor  in  the  French  Language  and  Literature. 

PA  LMER  CHAMBERLAINE  RICKETTS,  C.  E. 

Assistant  Professor  of  Mathematics  and  Astronomy. 

WILLIAM  PITT  MASON,  C.  E.,  M.  D. 

Assistant  Professor  of  Chemistry  and  Natural  Science. 

GUY  HARTWELL  ELMORE,  C.  E. 

Assistant  in  Rational  and  Technical  Mechanics. 

GEORGE  RICHMOND  BAUCUS,  C.  E. 

Assistant  in  Geodesy. 

JOHN  H.  EMIGH,  C.  E. 

Assistant  in  Geodesy,  etc. 

FRANK  LEWIS  NASON,  A.  B. 

Instructor  in  the  English  Language , and  Assistant  in  Mathematies. 
EDGAR  BOYD  KAY,  C.  E 

Assistant  in  Descriptive  Geometry  and  Drawing. 

JOHN  FRANCIS  WILLIAMS,  C.  E. 

Resident  Graduate  and  Special  Assistant. 


330  THE  RENSSELAER  POLYTECHNIC  INSTITUTE. 


COURSE  OF  STUDY. 

The  Course  of  Study  in  Civil  Engineering,  set  forth  in  the  following 
programme,  is  a new  and  much  improved  one,  differing  from  that 
hitherto  given  in  the  Institute,  by  including  Metallurgy  and  Free-hand 
Drawing,  with  special  extensions  of  Chemistry,  Physics,  Geology, 
Natural  History,  and  several  of  the  Practical  Subjects.  Hereafter  all 
regular  members  of  the  Institute  will  pursue  this  Course  of  Study, 
and  the  Degree  conferred  will  be  that  of  Civil  Engineer. 

By  the  aid  of  these  and  other  improvements  which  will  be  adopted, 
it  is  believed  that  the  Institute  can  furnish  the  student  of  Civil  Engi- 
neering with  facilities  for  the  study  of  that  subject  much  superior  to 
those  now  offered  by  any  other  institution  in  this  country. 

It  should  be  stated,  perhaps,  that  Civil  Engineering  is  understood  to 
include  Mechanical  or  Dynamical  Engineering,  as  well  as  Road  Engi- 
neering, Hydraulic  Engineering,  Bridge  Engineering,  etc.  By  refer- 
ence to  the  Programme  of  the  Course  of  Study,  it  will  be  seen  that  the 
wants  of  the  student  of  Mechanical  and  Mining  Engineering  have 
been  anticipated,  and  as  well  provided  for  as  could  be  possibly  done. 

The  studies  of  the  first  three  years  of  the  course  have  for  their  object 
the  establishment  of  a broad  and  substantial  basis  of  disciplinary  cul- 
ture— literary,  scientific,  and  artistic.  The  studies  of  the  fourth  year 
are  essentially  practical  and  technical. 

The  studies  of  the  course  are  designed  to  secure  to  all  who  have  duly 
complied  with  the  various  requirements, — in  other  words,  to  its  grad- 
uates— a Professional  preparation,  at  once  thorough  and  practical,  for 
the  following  specialties  of  Engineering  practice  : — 

The  location,  construction,  and  superintendence  of  Public  Works, 
as  Railways,  Canals,  Water  Works,  etc. ; the  design,  construction,  and 
management  of  Mills,  Iron  Works,  Steel  Works,  Chemical  Works,  and 
Pneumatic  Works  ; the  design  and  construction  of  Arch  Bridges,  Gir- 
der Bridges,  and  Suspension  Bridges ; the  design,  construction,  and 
use  of  Wind  Motors,  Hydraulic  Motors,  Air  Engines,  and  the  various 
kinds  of  Steam  Engines  ; the  design,  construction,  and  use  of  Machines 
in  general,  and  the  determination  of  their  efficiency  ; the  survey  of 
Rivers,  Lakes,  and  Harbors,  and  the  direction  of  their  improvements ; 
the  determination  of  Latitude,  Longitude,  Time  and  the  Meridian  in 
Geographical  Explorations,  or  for  other  purposes;  the  selection  and  test 
of  Materials  used  in  Construction  ; the  construction  of  the  various 
kinds  of  Geometrical  and  Topographical  Drawing. 


THE  RENSSELAER  POLYTECHNIC  INSTITUTE.  331 


TERMS  OF  ADMISSION. 

Candidates  for  Admission  to  Division  D are  thoroughly  examined 
in  the  following  subjects  : 

Geography. 

English  Grammar,  including  Spelling. 

Arithmetic,  as  treated  in  the  higher  text-books. 

Algebra,  through  Equations  of  the  second  Degree. 

Plane  Geometry,  first  five  books  of  Wentworth’s  Geometry. 

These  examinations  are  partly  oral  and  partly  written,  including 
both  the  demonstration  of  principles  and  the  working  of  examples. 

Advanced  Standing. — Candidates  for  advanced  standing  are 
examined  in  the  preparatory  studies,  and  also  in  the  previous  studies 
of  the  Division  which  they  propose  to  enter. 

Age. — No  one  can  be  admitted  to  Division  D,  till  he  has  completed 
his  sixteenth  year,  nor  to  an  advanced  standing  without  a correspond- 
ing increase  of  age. 

Testimonials. — Satisfactory  testimonials  of  good  moral  character 
are  in  all  cases  required  ; and  those  who  are  admitted  from  Colleges 
or  other  Scientific  Schools,  must  present  certificates  of  dismission  in 
good  standing. 

Young  gentlemen  desiring  to  attend  the  exercises  in  particular  de- 
partments, without  becoming  candidates  for  Degrees,  are  allowed  to 
do  so,  provided  they  have  the  requisite  preparation  for  the  study  of 
the  subject  selected, 

EXPENSES. 

Institute  Fees. — In  the  general  course,  the  fees  for  instruction, 
use  of  astronomical  and  field  instruments,  use  of  consumable  materials, 
chemicals,  etc.,  are  $100  for  each  semi-annual  session  ; and  in  the 
partial  course,  they  are  in  the  same  proportion  for  the  time  of  study. 
These  Fees  must  be  paid  to  the  Treasurer  in  advance  for  each  session. 
The  Graduation  Fee,  including  the  Diploma,  is  $18,  and  must  be  paid 
to  the  Treasurer  at  least  two  weeks  before  the  time  of  graduation. 
There  are  no  extra  charges. 

Living  Expenses.— Members  of  the  Institute  find  board  and 
lodgings  with  respectable  private  families  in  the  city.  The  prices 
asked  for  suitable  board  and  furnished  lodgings  vary,  at  the  present 
time,  from  $6.00  to  $10.00  per  week.  The  total  expense  of  board, 
furnished  lodgings,  laundry,  fires,  lights,  etc.,  varies  from  about  $300 
to  $500  for  the  scholastic  year. 

I Young  gentlemen  who  contemplate  taking  a thorough  course  in  the 
Natural  Sciences,  and  in  the  Higher  Mathematics,  with  a view  to 
fitting  themselves  for  the  professions  of  Civil,  Mechanical,  or 
Mining  Engineering,  should  apply  for  tjie  new  Register  for  1883 
and  ’84. 

Applications  may  be  made  to  David  M.  Greene,  C.  E.,  Director 
William  H.  Young,  Treasurer. 

JAMES  FORSYTH, 

President  of  R.  P.  Institute. 


Troy,  January,  1884. 


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